Absolute Zero Test by Jack Chilcott

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is for Antimatter

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In particle physics, antimatter is the mirror of matter; for every particle there is an antiparticle and when they meet they annihilate one another, resulting in a burst of pure energy. Einstein came up with the famous equation E=mc 2 . This equation relates energy to mass via "C" where c is the speed of light (a very large number). This means that extremely large quantities of energy are equivalent to quite small quantities of matter. For example, the energy contained in a single grain of sand is equivalent to the chemical energy in about half a tank of gas. When antimatter and matter annihilate they are converted to energy according to E=mc 2 . The discovery of matter-antimatter annihilation has helped confirm Einstein's equation.

matter

energy

(3 x 108 m/s)2

Antimatter is made of antiparticles, just like normal matter: an antitthydrogen atom is composed of an antiproton and an antielectron (a positron).

anti-hydrogen

The fact that the normal-matter universe exists at all is one that has baffled physicists for years. If nature provides an antiparticle for every particle, and they annihilate on contact, then the entire universe should be matter-less and composed of gamma rays. Physicists theorize that there must have been a slight imbalance of matter to antimatter creation in the few seconds after the Big Bang. Calculations accounting for the current matter in the universe show that the imbalance can actually be explained by one extra mattermatter pair per billion matter-antimatter pairs in the early universe. This process is called baryogenesis: ~ Erwin Schrodinger and Werner Heisenberg present the new ~ quantum theory of physics, however the theory was not

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relativistic (did not address particles traveling at light speed) ~

Albert Einstein unveils his theory of Special Relativity, explaining the relationship between space and time "'--~"""'!""ll"""-III

Paul Dirac combines quantum theory and special relativity to describe the behavior of the electron Dirac's equation, like x2 =4, has two solutions: one for an electron with a positive energy, and one for an electron with a negative energy. Dirac interpreted this to mean that for every particle there is an antiparticle! ~

Ernest Lawrence invents the cyclotron

Carl Anderson observes and christens

~ positrons while studying showers of rl

cosmic particles in a cloud chamber

Antiparticles occur naturally as a product of high-energy collisions, like those in Earth's atmosphere, but can be produced artificially using an accelerator. A particle accelerator bounces a normal matter particle between differently charged electromagnets until it is moving as close to the speed of light as possible, and then smashes the particle against a target to produce antimatter. Physicists study Each electromagnet these collisions to learn more about antimatter is longer than the previous, and how it behaves. which accelerates the particle. The particle's frequency remains constant: it has to "jump" to the next magnet in a set time, meaning its velocity increases as the lengths of the magnets increase.

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electromagnet Antimatter drives are popular in SciFi because of their high energy potential and conversion purity. When antimatter and matter collide they convert to gamma radiation, which is very energy-dense (containing approximately 5 million times as much energy as visible light). However, we cannot yet produce enough antimatter to be used as fuel- the number of antiprotons produced in the US in one year could only power a 100 watt light bulb for about 30 seconds! Storing antimatter is also difficult. Currently, there is research being done on electro-magnetic containment, but antimatter drive is still a thing of the future.

A practical application of antimatter is Postron Emission Tomography, or PET scanning. This technique uses electron-positron annihilations, which are relatively low-energy, to reveal the workings of the brain. These positrons come from the decay of radioactive nuclei that are incorporated in a special fluid injected into the patient. The positrons then annihilate with electrons in nearby atoms. Since the electron and positron are almost at rest when they annihilate, there is not enough annihilation energy to make a particle and antiparticle and the energy emerges as two gamma rays. The gamma rays shoot off in opposite directions and are detectable. Physicians can deduce that in places where there are more of these annihilations there are more electrons and therefore more brain activity. ~ Lawrence builds the Bevatron at Berkeley, ~

which could collide two protons at 6.2 GeV, expected to produce antiprotons ~ Antiproton produced and detected by

~ Ernest Lawrence and Emilio Segre

~Team at Berkeley announces ~ discovery of the antineutron

tBTwo teams observe the antideuteron ~ (an anti nuclei comprised of an antiproton and an antineutron)

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Team of German and Italian physicists slow anti nuclei and positrons to force them to create antiatoms (9 antihydrogen atoms created)

The Beginning of Our Universe Some of the bigest questions have been: How did we get here? Where did we come from? Where are we going? People called Steady State Theorists believe that our universe has been around forever and is infinite, but through the theory of the Big Bang, assuming that the universe is infinite is wrong. The Big Bang Theory suggests that the whole universe came from one initial explosion tht laid out the foundations of the universe. The Big Bang happened about 15 billion years ago and expanded the whole unverse to what it is today. One of the biggest arguments that the Steady State Theory doesn't stand up to is the idea that every galaxy in the universe moves at a directly proportional rate to one another. If the galaxies move at this rate, if this rate is reversed, it would lead to every galaxy coming from one central place and time.

The Age of Our Universe In 1936, Edwin Hubble observed two components to finding out how old our universe is: galaxies' red shifts and galaxies' distances moving away from ours. A red shift is when a galaxy has a longer wavelength as it moves farther away from our galaxy. Hubble o perceived that galaxies that are moving away from each other move at a directly proportional rate. For example, if a galaxy is twice as far from another galaxy, it's moving twice as fast as the other one. From this, Hubble figured that if galaxies were moving at Dr. Edwin Hubble a directly proportional rate, reversing this process would lead to each galaxy coming from one place at one time. Hubble measured the distance of the farthest star from our galaxy by its intensity, which equaled time. This is the equation Hubble used:

distance ofparticular galaxy particular galaxys red shift

time

with this equation in hand, Hubble plugged in the numbers:

4.6 X 1026 centimeters lxl0 9 centimeters/sec

4.6 X 1017 seconds

4.6 X 1017 seconds is equivalent to approximately 15 billion years.

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A side view of the big bang. As the big bang happened, the universe was very hot (billions of degrees kelvin !), expanded outward and cooled to its temperature now (about 3 degrees kelvin). (

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The picture below depicts the process of the Big Bang. Here's what happened:

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1. 10-43 seconds, temperature begins: cosmos begin expanding. 2. 10-32 seconds, 10 27 degrees celsius: universe is hot plasma stew full of particles like electrons and quarks. 3. 10-6 seconds, 1013 degrees celsius: protons and neutrons begin forming. 4.3 minutes, 108 degrees celsius: universe is a giant, hot cloud, protons and neutrons are present but is still too hot to form atoms. 5.300,000 years, 10,000 degrees celsius: Electrons, protons and neutrons combine and create heluim and hydrogen atoms; light begins to shine. 6.1 billion years, -200 degrees celsius: Gravity makes hydrogen and helium molecules create giant clouds that soon became protogalaxies. 7. 15 billion years, -270 degrees celsius: Galaxies form together because of the presence of gravity; stars die and create the planets we know today.

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for Climate Change

Climate defines the weather patterns across the world. It includes temperature, atmospheric pressure, humidity, and rainfall. Different locations around the world have varying climates, but there are also some global trends. These trends can be seen throughout Earth's history over long periods of time, such as ice ages and global warming. These trends are affected by the orbit of the earth around the sun, the sun's intensity, and the changes in the efficiency of the Greenhouse Effect.

The Green house Effect The Greenhouse Effect is what warms the Earth enough to make it habitable by humans. To gain an understanding of this phenomenon, we must consider the role of the atmosphere in the environment of our planet. The atmosphere contains greenhouse gasses - gasses that absorb infrared radiation. These gasses include things like carbon dioxide (C0 2 ), water vapor, methane, and ozone. Visible light from the sun shines through the atmosphere and warms the Earth. The Earth then emits this heat as infrared radiation sending it outwards. Greenhouse gasses in the atmosphere stop much of the radiation from escaping to space by absorbing and re-emitting it. This sends heat energy back to Earth re-warming it.

Some of the sun's rays are reflected by the atmosphere

Some of this infrared radiation leaks through to space

One single chlorine atom can destroy over 100,000 ozone molecules!!

When the ozone layer decreases by 1%, UV ray exposure to the earth increases by 2%.

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Without the atmosphere, infrared radiation emitted by the Earth wouldn't be re-absorbed, and the temperature on Earth would only be 26째F.

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The Earth hangs in a delicate balance between hot and cold. An increase or decrease in greenhouse gasses has the potential to disrupt this balance. First, consider the Earth without an atmosphere. The average temperature on Earth would be about 26째F. The surface of the oceans would be frozen and our planet would be a completely different place. From an alternate perspective we can look at the global warming we are currently experiencing. Many of the gasses that we emit as industrial byproducts are greenhouse gasses. This causes the atmosphere to absorb and emit more infrared radiation, which in turn warms the Earth. The difference of a few degrees would cause more water to evaporate sending more water vapor into the air. Water vapor is one of the most effective greenhouse gasses; therefore, the more water vapor, the warmer our Earth's temperature will climb. Although it may have been simple to start this process, stopping it is a whole different matter.

The ozone hole affects our climate in a different way. Similar to the greenhouse effect, sunlight plays a major factor in this phenomenon. In addition to visible light and infrared radiation, sunlight also consist of something called ultraviolet (UV) light. Exposure to UV light is what causes sunburns, skin cancer, and mutations in DNA. This is because the Ozone molecules are photons of UV light have much more energy than that of visible light or drawn as resonance structures, meaning infrared radiation. This energy also enables it to break up 02 molecules the double sigma in the atmosphere into two separate oxygen atoms. These atoms go on bond can be on to attach to non-broken 02 molecules creating 3 , or ozone. The either side of the produced ozone is an effective absorber of UV and therefore creates molecule. more ozone. In this way, the atmosphere is able to adapt to an increase or decrease in the intensity of the sun. The more UV that shines toward the earth, the more ozone is created to protect us from the harmful rays. The opposite is also true, sometimes resulting in something called an ozone hole. During the winter, the South Pole gets little to no sunlight, so with no UV to create it, the ozone layer disappears over this region. Unfortunately this is not the only contributor to ozone depletion. Some believe that pollutants from man made sources such as the chemical Freon (used in old refrigerators and air conditioning units) can lead to the destruction of ozone. Freon and some other pollutants contain chlorine, fluorine, and carbon and are called CFCs. These CFCs are highly stable until they float into the upper atmosphere. There they sit until ultraviolet rays hit the molecules, causing them to split into single chlorine (CI), fluorine, and carbon atoms. Chlorine and fluorine are then free to attack the ozone molecules sending them back to the 02 state. Fortunately, an agreement was made called the Montreal Protocol which has resulted in a drastic drop in the emissions of CFCs. Here are the reactions that occur between carbon and ozone molecules:

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cia + cia + sunlight

. . . . CI + CI + O2

Now, the two leftover chlorine atoms are free to attack more ozone molecules and repeat the reactions.

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Christian Doppler

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In 1842, a man named Christian Doppler discovered that objects that are moving emit sounds at a different pitch than things that are stationary. His theory was that the observed change in frequency of the sound wave is due to the motion. To further test his theory, he had 15 trumpeters playa single

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note on a moving train. He observed from the side of the track. When the train passed him, he was able to measure the change in pitch and thus quantify what we now call the

The sound waves in the front are scrunched up and the sound waves in the back are stretched out to demonstrate that the source of the noise is moving faster.

Doppler Effect. The reason that we observe the Doppler Effect can be explained by using the idea of waves. It is similar to when you're at the beach, standing in the water, letting the waves

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crash at your feet. The waves will hit you more frequently if you were to walk toward the waves as opposed to standing still. The frequency increases when the source and observer are moving towards each other. If they are moving apart, the frequency shifts lower.

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When the observer is moving towards the source, you add and when he is moving away, you subtract.

In 1845, Christoph Hendrik discovered that the Doppler Effect occurs in light waves. Just as sound waves get a frequency shift when the source is moving, stars that are moving relative to us give out light that is shifted in frequency. This changes the color of the light towards blue if the object is moving closer, red if moving away. Edwin Hubble measured the shift in the light from distant galaxies and compared it to how far they are from Earth. The shift is determined by the position of certain wavelengths due to an element in the star's spectral lines compared with their position on a "laboratory- produced" spectrum of colors. If the light is shifted up in frequency we call this "blue shift" and we conclude that the galaxy is moving towards us. When the galaxy is moving away the spectrum moves towards the red side of the spectrum. (red shift) Hubble found that nearly all galaxies we see are moving away from us and the speed they are moving at is in direct proportion to the distance from us. What he concluded from this is that our universe was made at a single point in time. This idea has since led to Big Bang theory.

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an abundance or an absence of electrons. Electrons, which

are negatively charged sub-atomic particles, drive the modern world. From appliances to vehicles, all technology relies upon this particle's movement through a circuit. The electrons move in a current, similar to water's movement in a river, and the activity of electrons in the circuit they are contained within is measured through a relatively simple equation called Ohm's Law.

Measuring Electric Currents Georg Simon Ohm, a German physicist, discovered that the voltage in a circuit is the product of the current and the resistance. Thus:

V=IR V is voltage, also known as the 'potential difference'. Voltage is similar to water pressure in a hydraulic pump. I is current (measured in amps), and refers to the number of electrons passing a specific point in once second. Finally, R is the resistance (measured in ohms), and it reflects the conductors resistance to the flow of the electric current. Electricity moving through a circuit is often compared to water moving in a hydraulic pump. The amount of water flowing past a point every second can be compared to amps, while the water pressure is similar to voltage. Finally, the pressure the hydraulic pump exerts can be compared to a circuit's resistance.

Using Electricity to Do Work When electricity flows through any material, it naturally encounters resistance. Materials with low resistance (such as copper) are called conductors, whereas materials with high resistance (such as rubber) are called insulators. The resistance extracts energy from electric currents, and converts it into other forms of energy, often thermal. In a lightbulb, the filament has a high resistance to the flow ofthe electric current. As the electric current flows through the filament, the resistance converts the electric potential difference (volts) into thermal energy (heat). In a lightbulb, the heat is so intense that the filament glows orange or white hot, which produces the visible light. Everything has resistance, (unless you start talking about Superconductors, '5'), and that resistance turns the electric energy into heat.

~~~~ยง-; While converting electricity to heat is a simple matter, converting it into kinetic ~ energy is a more complex affair. It involves one of electricity's intrinsic properties: its innate ability to electromagnetism.

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Hydroelectric Power Hydroelectric power is electrical power which is generated by converting the energy of falling water. Hydropower provides about 96 percent of the renewable energy supply in the United States. Hydroelectric power plants collect water behind a dam to build up potential energy. Potential energy definition is energy that is stored within an object. For example, when water is not moving it has potential energy because of earth's gravity. When water starts moving through a dam, the potential energy is converted into kinetic energy because the water is moving. Combining potential energy and kinetic energy can make mechanical energy by moving the water to the turbine.

Modern Hydroelectric Dams A hydroelectric power plant converts the potential energy of water into electricity using the gravitational force of falling or flowing water. Water must fall in order to generate power from a stream. The process begins when water flows through a dam containing turbines. When water starts spinning the turbines, the turbines will turn on the generators that make electricity and the electricity is transferred to the power lines. When constructing a dam engineers have to have a highly technical understading. They have to gather extensive field data in order to chose the best site to design an excellent safe dam. Head water The Formula for calculating power output in kilowatts of a hydroelectric dam is:

KW= 0.0846/E X Q X H

Power lines

Potential Energy

Dam

Q= Water flow, cubic feet per second H= Head, feet E= Efficiency of hydroelectric plant, percent divided by 100.

Howa Hydroelectric Turbine Works: The pictu re to the right is a tu rbi ne that converts the ki netic energy of water flowing into mechanical energy. The energy that is gathered by the flowing water is channeled it through a hydroelectric generator. Which converts that mechanical energy into electricity. The operation of a generator is based on the principles discovered by Faraday. He found that when a magnet is moved past a conductor, it causes electricity to flow.

Modern Wind Turbines A wind turbine is a machine that uses the movement of air to do work. Historically, windmills have been used to pump water and grind flour. Modern wind turbines focus on converting wind power into electricity. The turbine blades are angled for maximum wind capture and connect to the low speed shaft. The high speed shaft, which drives the generator, is connected to the low speed shaft by a gearing system.

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Catching Wind Today, we have sensors and motors built into the wind turbine to make them turn toward the wind. The anemometer and wind vane make up the sensor. They report the information to the computer, which then processes and passes the information to the motor. The motor moves the turbine.

The formula for calculating the amount of watts from your Windmill is:

2CpPAV3

Cp - estimated windmill's performance. A - the swept rotor size in square meters V - the mean annual wind speed

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How Wind is Created Wind is created when the sun unevenly heats the land and the ocean, causing hot air to rise at different rates over the Earth. This gives rise to areas of high and low pressure within the atmosphere. The atmosphere tries to equalize the different areas the different atmospheric pressures. As the atmosphere tries to equalize the pressures, air flows from one area to another.

Pm - the acquired amount of watts. Modern wind turbines have special brakes to slow the rotor and to prevent the generator from overheating. A generator can only reach a certain total amount of output before it becomes inefficient and burns out. Normally, A wind turbine can only withstand speeds of 35-55 mph {miles per hour}. The brakes completely stop the wind turbines.

Electromagnetism Electromagnetism refers to the influences of the electromagnetic force, one of the four fundamental forces in physics on which all others are based. The electromagnetic force is responsible for things such as friction, and plays a huge role in our everday lives. In the same way that masses produce gravitational fields, electric currents create electromagnetic fields. An electromagnet can easily be made by wrapping a copper wire around a cylinder, and then applying electric current by connecting the wire to a battery. All magnets have poles, and electromagnets are no exception. Interestingly, the poles are not influenced by the geography of the cylinder; instead, it is based upon the movement of the current. This is how electric motors operate.

Fundamentals of an Electric Motor N

The electric current passing through the nail created a magnetic charge, with the north pole positioned near the end of the circuit.

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The north end of the electromagnet is attracted to the south of end of the horseshoe magnet, and vice-versa, which causes the nail to spin.

If one subsequently flips the battery, the electromagnet's poles will reverse.

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As a result, the nail will flip once more. In an electric motor, the "nail" would be attached to an axle. That way, when the nail spun, it would spin the axle.

While this diagram shows the forces at work in an electric motor, it is extremely simplified. In a real motor, the spinning would drive an axle, which could then drive, for example, a wheel. In addition, the battery must cycle two times for every rotation, in order to return to the 'initial' position.

Converting Kinetic Energy into Electricity While electricity can be converted into kinetic energy through electromagnetism, the opposite is also possible. At its core, everything from nuclear reactors to coal-burning plants use kinetic energy to spin a turbine, which uses a magnet and copper wire to induce the movement of electricity. Of particular note are hydroelectric dams and wind turbines, which use ambient energies that would otherwise go unharnessed.

F Is for Force

Force is an act such as a push or pull that causes an object with mass to change its acceleration. All forces act in a certain direction and have a size (or magnitude) based on the strength of the push or pull. It is impossible to find the force of an object if either the direction or the magnitude of the force is absent. Mass is important to force as it can alter the result of an equation. For instance, If an elephant is being pushed up hill by a mouse, the mouse would need to exert more force than the elephant, if the roles were flipped.

F=ma There are various equations used to find the force exerted on an object. A common force equation is F=ma. F=ma is used to find the force applied to an object in motion. The m in the equation stands for mass. The a variable stands for the acceleration. For instance, if asked what the force applied on a 1 kg ball being 2 kicked at 10m/s was, the acceleration would be 10 m/s 2 and the mass would be lkg. The unit used for force is the Newton. One Newton is equivalent to 1 kg m/s 2 . When you multiply a mass which is measured in kilograms by an acceleration which is measured in m/s 2, you end up with kg m/s 2, changing the units to Newtons.

Sir Isaac newton (1642-1727) Isaac Newton published principa His book principa in 1687. was his most recognized peice of work, explaining his ideas of universal gravity and the three laws of motion.

Rocket Thrust Rocket th rust is the force wh ich moves the rocket through the air and through space. The basis of finding out the thrust force on a rocket is knowing the mass and velocity of the hot gas being burned from the rocket. As the gas from the rocket is exerted from the exhaust, the rocket is propelled with a forward motion. What determines how fast the rocket is propelled is how much gas comes out of the exhaust and how fast it is being pushed out.

Gravitational Force Gravity is defined as a type afforce, as it causes an objects velocity to change when being dropped or thrown in any direction. Any two objects that have mass, attract each other with a force known as gravity. The smaller an object in mass the smaller the force exerted. For instance, the gravity on the Moon is far less than that of the gravity on Earth, because the Moon has a smaller mass. This explains the reason why the Moon revolves around the Earth and the Earth revolves around the Sun.

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Torque It may seem obvious, but the handles on doors are placed on the other side of the hinges so that it is easier to turn the door. If the handle were to be placed near the hinges, then the door would require much more force to tu rn.

Torque is the measure of how much a force causes an object to rotate rotates around an axis. Torque is defined as:

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The radius (r) is the distance from the axis to the point where the force is applied. Force (F) refers to the force that is applied that causes the object to rotate about its axis of rotation. In other words, torque ("r) is the product of the radius and the force. Because of this, torque can be easily increased by increasing the force, or simply increasing the distance from the axis (the radius). This means that rotating an object will become much easier as there is a greater radius used to generate the torque. Torque is generally measured in either pound-foots or Newton-meters. This is because when measuring force in pounds, the radius must be measured in feet, and when measuring force in Newtons, the radius must be measured in meters. Some other units such as work are measured by Newtonmeters and foot-pounds (products of force and distance). Work would refer to force applied in the direction of the radius. Torque is unique because of the fact that the force is applied at a right angle to the measured radius.

Using the right hand rule, we can find the direction of the torque. If we put our fingers in the direction of the radius (red) and curl them to the direction of the force (green), then the thumb points in the direction of the torque (yellow).

Imagine turning a wrench to tighten a bolt. The force of your pulling causes the wrench to rotate about the bolt. How hard you need to pull depends on the distance your hand is from the bolt. The closer your hand is to the bolt, the more force it takes to tighten it.

Try balancing a meterstick on top of your index fingers. When you slowly bring your two fingers together, you may notice that they meet at the center eveyry time. This is because the torque applied by each finger to keep the stick balanced is different, causing the frictions to change while the fingers are at different points on the stick. This is an ideal example of how friction and torque can work together to perform phenomonal tasks.

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Galileo Galilei (1564-1642)

is for Gravity

The first recorded scientist to study Gravity. His experiments involved dropping objects to see how they fell.

Acceleration of Gravity

Gravity is an attractive force that occurs between any two objects that have mass. How powerful that force is depends on how large each mass is, and the distance between them - gravity is stronger for large masses, and decreases as the objects get further apart. The strength of the force can be found through the following equation:

F Gravity is the reason that when you drop an item, it falls to the ground. The forces between the large mass of the Earth and objects on its surface are enough to accelerate the objects by a standard rate of 9.8 meters per second squared. When you drop two items, no matter their mass, you will see that they accelerate at the same rate and hit the ground at the same time. This is due mainly to Inertia - a property that any object with mass exhibits. Even though a large mass has a large force pulling it to Earth, the object's mass requires a larger force to move it at a similar rate to a smaller object.

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Weight Gravity is a key player in the workings of the universe. It keeps planets in orbit and provides a basic, yet constant force. One common product of Gravity is weight. Weight is a measurement of the force towards the center of Earth's mass, caused by gravity. It can be found by taking the mass of an object and multiplying it by the acceleration of gravity due to Earth's mass, which as we established is roughly 9.8 meters per second squared. However your weight on Earth will not be the same as your weight if you were to stand on the Moon. Because the Moon has a different mass, it will pull you towards its center with a different force. Because the Moon's mass is smaller, it would pull you in with less force, causing you to weigh less on the Moon.

The Earth and the Moon We on Earth feel the pull of the Moon much more than the pull of the Sun (many people think that because of the tides, the Moon's gravitational pull is the greater). In reality, the force of the Moon's gravity on Earth is much smaller than that of the Sun's. Think of being on a roller coaster: when you make a turn, you feel the bumps in the track a lot more than the force of the turn even though the force that you're turning with is much more than the force from the bumps. We are rotating around the extremely large mass of the Sun, but as we, the Earth and all things on it are moving together we are unaware of its effect. The force of the Moon causes a small perturbation to this force (similar to the rollercoaster's bumps) but produces noticeable effects, such as the tides of the ocean. Tide rotation, where the water levels of the Earth's oceans rise and fall, is a direct consequence of the Moon pulling mass towards it. Newton correctly theorized in 1687 that the Moon pulls on the Earth and its water, however the Moon's force across Earth varies because the Earth is spherical. The side facing the Moon is under more force than the side away from the moon, thus stretching the water levels from their spherical shape around the Earth.

Orbit One of the most visible effects of gravitational attraction is the tendency of celestial bodies to travel in curved paths around other objects. A good example of this is the orbit of the planets around Q the sun. Because the sun has such a large mass (around 333,000 0.; times the mass of Earth) its gravitational pull attracts all other objects in the solar system. While the planets in our solar system are in a nearly circular orbit around the Sun, other bodies such as asteroids and comets travel in elliptical paths around to the Sun. The planet's orbits are relatively stable - circular orbits at different radii do not cross. An orbit that has the shape of an ellipse will send asteroids close to the sun at one point and far from it at another. This path may intersect with Earth's orbit, making an impact a real and worrying possibility.

The Moon's Orbit When you look up at the Moon in the night sky you notice that its appearance changes from night to night. As the Moon orbits the Earth, it displays a specific set of characteristics depending on its position relative to the Earth and the Sun. As seen in the diagram below, there are 8 distinctly recognized stages the Moon goes through when it orbits around the Earth. The orbit of the Moon is "tidally locked" meaning that frictional forces occurring from the tides have stopped the moon rotating relative to the Earth. The Moon actually turns at exactly the same rate that it orbits us, meaning that we see the same portion of the Moon facing us at all times. The notion of the "Man in the Moon" comes from light and dark regions on the lunar surface that always appear the same way up.

Phases It takes around 29 days for the Moon to orbit the Earth. During this time, the Moon gradually progresses between phases. It first starts off as a New Moon, which is when the Moon is directly between the Earth and the Sun. At this time the Moon is not visible from Earth (it appears in the sky during daytime and only the unlit side faces us). Next is the waxing crescent, where less than half of the visible Moon is illuminated. During this phase, more of the visible side is illuminated each night. The first quarter occurs when the Moon is directly 90 degrees from the Earth and the Sun. In this position exactly half of the visible Moon is illuminated. Next is the waxing gibbous, this is when more than half of the visible Moon is illuminated. The Full Moon is when the Earth is directly between the Moon and the Sun. When the Moon is in this phase, its visible side is fully lit by the sun. After the Full Moon, the waning gibbous occurs, this is similar to the waxing gibbous where more half of the visible Moon is illuminated. Before the cycle starts over again, the Moon goes through a phase similar to the waxing crescent. During this phase, known as the waning crescent, less than one half of the visible Moon is lit. This final phase can be thought of as a mirror image of the waxing crescent, but now less of the visible side is lit each night.

is for Hologram Like photographs, holograms record light onto film. Unlike photographs, when holograms are viewed the objects in the recording move according to the position of the viewer. This makes the recorded image seem three-dimensional by creating an illusion of depth and position. In addition, each individual eye picks up a different facet of the image and the brain combines the two seperate images, further contributing to the illusion of depth. Holograms need to be recorded with a specific kind of light known as 'coherent light'. Coherent light is defined as light whose waves are in phase with each other; this means that the waves are traveling with the same period and frequency in a parallel motion. In this way coherent light is similar to soldiers marching in lock step. All are moving together, in the same direction and in step. This differs from the light provided by ordinary household light bulbs, which glow hot and distrubute random thermal emissions. This light is 'incoherent;' the light waves can be compared to a shopping mall at Christmas time in which everyone is moving in all different directions and speeds. The coherent light used to record holograms is provided by a high power laser.

Coherent Light

Incoherent Light

Lasers create coherent beams by stimulating atoms to emit light. Stimulated atoms have higher energy electrons and return to a ground state by emitting energy in the form of photons in a laser cavity. These photons form a beam of monochromatic coherent light. Holograms also require very high resolution film because patterns recorded onto the film need to be accurate to the wavelength of light. The pixels per inch (DPI) equivalent of this resolution requirement exceeds 30,000 DPI. That is why holograms currently require emulsion film.

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••

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Object

...•..-

A beam of coherent light, usually provided Mirror by a laser, is directed through a beam expander I I that acts like a reverse telescope. This causes the beam • to widen. This beam goes through a beam splitter, a •••• semi-silvered mirror with a partially reflective surface. I Reference Beam----.I Half of the light goes in one direction to strike the emulsion film. The other half goes in another direction, off of the object, and then onto the emlusion film. This is known as the incident beam. The light reflected from the beam spreader is diverted so that it runs parallel to the incident beam. Those beams are reflected once more by a mirror and onto the emulsion creating a reference beam.

•

When the reference and incident beams strike the emulsion film, they combine to form an interference pattern. The interference causes 'fringe patterns' to be recorded onto the film.

Incident Beam I

Fringe Patterns

I I I I I I1• • • •

Holograms are the recordings of these fringe patterns. If the incident beam and reference Interference Pattern I beam that strike the film are in phase then I I the interference is constructive and light will be visible at that poi nt on the film. Conversely, if ~ Reference Beam the reference and incident beams are 180 degrees out of phase, they cancel each other out. This is destructive interference. There will be no light visible on the film at those points. I I I I

In order to retrieve the information stored on the film coherent light produced by a laser beam is shone through it. This new reference beam interacts with the pattern left on the film; the fringe pattern. The diffraction occuring between the light and fringe pattern combine to allow the image to be reconstructed. Though the object is no longer there, it can still be seen on the film and appears to be 3D.

Ji;;~~\' - - - -

------

lis

for Inertia

Before Newton, people believed in the Aristotelian view. Aristotle had different laws of motion for earth-bound objects and celestial bodies. Essentially, Aristotle's law stated that in the absence of forces, anything on earth will eventually slow down and stop. t

Newton's laws of motion are universal - they apply to all objects in the entire universe. His first law states that an object in motion continues to move at the same speed and the same direction unless acted upon by another force. This is often called the law of inertia. If a person is standing on a skateboard, then he will not move unless some other force pushes or moves him. If a person is riding a skateboard down the street and hits an object such as a curb, the person will continue to go in the same direction and speed. Although the skateboard has stopped, the person's motion continues in the same direction and same speed that it was initially going.

Another example of inertia is when a space shuttle takes off and is boosted into orbit around the earth. Initially, astronauts fire up the engines to gain the height and speed needed to \ leave the earth's atmosphere. Once high enough, the astronauts shut off the engines, and the space \ shuttle stays in orbit because of inertia.

/ (

I ( r

lin space, there is no air resistance but there is still the affect of gravity. The combination of inertia [which keeps the space shuttle moving at / a constant speed] and gravity cause the shuttle to move in an unchanging circular path.

\ \ \

/ /

Both of these examples show how objects resist changes to their motion - it is this resistance to change that we commonly call inertia.

Newton's Second Law Newton's second law states that the force applied to an object will produce a corresponding acceleration. This acceleration is dependent on the mass of the object: a given force can move a large mass at a low acceleration or a small mass at a large acceleration. This applies to individual objects as well: a large force will move an object with a large acceleration, while a smaller force will cause it to move with a proportionally smaller acceleration. The images below have the equation force equals mass times acceleration. If the mass of the object is small, such as a golf ball, then the acceleration is greater. While a larger object, such as a bowling ball, has less acceleration because of its greater mass.

IF=ma I

Momentum A consequence of Newton's second law is the concept of momentum. Momentum is the product of an objects mass and velocity. It is similar to inertia in that it helps to quantify how long a force needs to act on an object to speed it up or slow it down: The way to solve for any of these is to use the equation below.

== mv == Ft

p=momentum, m=mass, v=velocity, F=force, t=time I.

~,~

, , - / Newton's Third Law Newton's third law states that for every action there is an equal and opposite reaction. This explains that when one object applies a force on another object; the second object puts a force of equal strength in the opposite direction on the first object. For example, if a man fires a shotgun, once he shoots the gun he will feel the "kick" from the force upon the shotgun which is equal to the magnitude to the force that pushes the pellets. In the image to the left, the blue arrow represents the force applied to the bullet being shot out of the shotgun and the red arrow shows the direction and momentum in which the gun recoils through because of the force of the bullet exerts on it. The last force working in this example would be that of the bullet hitting the target. In movies, when a person is hit by a bullet they are often thrown violently backwards. Ifthis were to happen in reality, the person firing the gun would get an equally violent "kick" from the recoil of the gun.

Jis for J.J. Thomson J.J Thomson was born in 1856 in Manchester England. He was alsocavendish professor of physics and had Ernest Rutherford as his student. The Plum Pudding model resembled a round positively charged sphere with negatively charged electrons randomly placed throughout it. There was no concept of a central nucleus in this model. This resembled an English plum pudding with the static electrons in place of the plums. Created by J.J. Thomson, the model was proposed to the public in 1904. This was before the discovery of the atomic nucleus and therefore was disproved when the atomic nucleus was discovered. The Rutherford model (below) was modeled like the modern solar system, with the nucleus as the sun, and the electrons as orbiting planets. This model is not in fact totally correct but has some correct factors, like how there is a nucleus in the Vacuum center, how the electrons are surrounding the nucleus, and that the electrons give an atom it's size. The incorrect factors of this model include not showing the correct energy levels, .-

allowing the electrons to orbit any <Âą) (i) where and lastly that ' the model could not explain why the electrons did not spiral inward.

Rotateable Mic oscape

Neil Bohr's model is a modification of the Rutherford model. In Bohr's model the electrons are described by a wave function. Bohr thought that electrons could only go where a whole number of wave lengths fit into the orbit. What is right about Bohr's model is it explains why only certain orbits are allowed, that it correctly predicts Spectral line energy levels and transitions, Nucleus and how it takes the Rutherford model and quantum applies mechanics to it. The only real flaw in Bohr's model is that it is too simple to even describe something as easy as hydrogen perfectly, although it accurately describes the n = 3 basic principles. Electron Orbit

K is for kinetic energy Kinetic energy is the energy that an object has because of its motion. The direction of the motion does not matter; any object with motion has kinetic energy. Kinetic energy is equal to one-half the product of an object's mass and the square of its velocity. 2

As an object falls, it accelerates and potential energy is converted into kinetic energy. The potential energy becomes entirely kinetic energy immediately before impact with the ground. At each point of the object's descent, the sum of the kinetic and potential energy is nearly constant. However, some energy is lost while the object heats up due to wind resistance. Mass is measured in kilograms â&#x20AC;˘ Velocity is measured in meters per second â&#x20AC;˘ Kinetic energy is measured in Joules

A yo-yo would have its maximum potential energy when it is being held in a person's hand above the floor. As it begins to unwind and fall, the potential energy is gradually converted into kinetic energy. Virtually all the potential energy is transformed into kinetic energy once the yo-yo is spinning at the bottom of the string. As the yo-yo travels up and down, it is repeatedly exchanging potential and kinetic energy. In addition to linear kinetic energy, the yo-yo also has rotational kinetic energy when it is spinning, similar to a flywheel.

The amount of kinetic energy one object can yield depends on v 2 â&#x20AC;˘ Because velocity is squared, an object moving at 100 meters/second has one hundred times the kinetic energy than it would have if it was traveling at 10 meters/second. A car moving at 60 miles per hour has four times the kinetic energy of a car moving at 30 miles per hour. Because kinetic energy quadruples as velocity doubles, accidents at high speeds become incredibly dangerous! In a crash, energy is used to crush the car and a great amount of force is exerted on the vehicle's occupants.

is for light Light is a form of energy that is carried by electromagnetic waves. These waves are produced by the motion of electrically charged particles. There are many examples of electromagnetic radiation - the name we give each one depends on the frequency of the wave. Low frequency gives rise to radio waves while very high frequencies create X-rays. The continuous range of frequencies is known as the electromagnetic spectrum, and the narrow band that can be detected by the eye is called visible light. The wavelengths of visible light are between roughly 380 nm and 740 nm. Wavelengths outside that spectrum cannot be seen by the human eye.

t:~I~I~ 600

Wavelength

500

400

A measured in nanometers (nm)

White Light Monochromatic light is light of a single color and a single wavelength. For example, monochromatic light at 500 nm appears turquoise while monochromatic light at 600 nm is yellow. White light consists of all the visible wavelengths at once. When we pass white light through a triangular prism, it separates into its component colors. The separation of visible light occurs because light waves bend by varying amounts depending on their wavelength. This is known as dispersion.

---:::~~~• • •Red

Orange Yellow Green Blue Indigo Violet

Glass Prism

Color Vision The human eye and brain work together to translate light into color. Light receptors within the eye transmit messages to the brain that produce the familiar sensations of color. Inside our eyes are cone cells that help provide us with color vision: an S cone (short wavelength: blue color detection), an M cone (medium wavelength: green color detection), and an L cone (long wavelength: red color detection). Red, green, and blue are the additive primary colors of the color spectrum, and by carefully combining these colors, we can create an optical illusion tricking the brain into thinking we are looking at colors that are not really there. For instance, when we see yellow on a computer screen, we are not looking at 600nm yellow light. The color is produced by the green and red region of the color spectrum. By varying the amount of red, green, and blue light, all of the colors in the visible spectrum can be produced. 1.0

>.:;

7.5

+-'

:-e Vl

0.5

2.5

0.0 400

500

600

700

Infrared and Ultraviolet Light There are many types of light that make up a band of radiation frequencies called the electromagnetic spectrum. Every single type of electromagnetic radiation transfers energy through waves of oscillating electromagnetic fields. We are able to classify each type of radiation by its frequency and wavelength. There are five main types of radiation on the electromagnetic spectrum: radio, microwave, light (both invisible and visible), x-ray, and gamma ray. Infrared radiation (lR) and ultraviolet light (UV) are types of light that are invisible to the naked eye. The reason we cannot see infrared radiation is because its wavelength is outside the range of human vision. Visible light ranges from wavelengths of 380 nanometers to 750 nanometers. The wavelength of infrared radiation ranges from 700 nanometers to 300 microns. Red has the longest wavelength on the color spectrum, so infrared light is sometimes referred to as "redder-than-red". Infrared radiation is usually emitted by objects that absorb and reflect heat. An example of this is when a piece of aluminum foil is placed in the sunlight. Eventually, you will be able to feel the heat energy radiating off of it. It is also hot to the touch.

Infrared

Visible Ught

Ultraviolet

In the graph above, you can see the order of wavelength from longest to shortest. The three types of radiation shown are infrared radiation, visible light, and ultraviolet radiation.

Aluminum foil absorbs infrared radiation and reflects it. As an object's temperature increases greatly its infrared radiation gets closer to becoming visible light. Infrared itself is not heat; the energy of the radiation is what causes an object's heat to increase. Intense infrared radiation can damage or burn living cells, killing them. Thermal imaging cameras use infrared radiation. By using specially cooled ccd arrays, cameras can be made that are very sensitive to low levels of heat. These cameras can be used for tracking people, night vision, astronomy, and weather prediction amongst many other uses. Other forms of light can also be imaged in this way: ultraviolet light imaging can show damage to skin and also to crops. Art historians often find surprises when they look at ultraviolet, infrared, and x-ray images of art works. Ultraviolet light, like infrared radiation, cannot be seen by the human eye. Its wavelengths range from 10 nanometers to 400 nanometers. The name "ultraviolet" came from its electromagnetic waves that have frequencies that are higher than the color violet.

Dentists use ultraviolet light to create a chemical reaction in the paste used to fill teeth. Once the paste comes in contact with ultraviolet light, it hardens and creates an invisible filling.

UV light can be found in sunlight. When you get sunburned, it is because of UV light's effect on human skin. The UV radiation mutates the DNA in our skin cells, causing them to die. Our body then has to shed those skin cells and produce new ones. There are two types of ultraviolet light. UVA is the longer wavelength of ultraviolet light, and UVB is the shorter. UVA can lead to skin cancer. UVB, the shorter wavelength of ultraviolet light, usually just causes sunburn.

Lasers Lasers have become a staple of the digital age. They are used in a variety of different things, from CD and DVD readers, to cutting diamonds, to eye surgery. Yet not many people actually understand how they work. There are several different types of lasers, but they all share some fundamental traits. All lasers work by first causing the atoms of an "active medium" to enter an optically excited state. When an atom becomes excited, one of its electrons absorbs extra energy, causing it to jump to a higher-energy orbit. Only certain materials can be used as a medium, but the material can be a solid, liquid or gas. The first lasers used a ruby crystal as a medium. Most lasers excite the atoms by shining a bright light into the medium or sending pulses of electricity into the medium. Electrons in a high-energy state eventually wish to return to their ground state, so at some point the energized electrons hop back down to ground state. For a Ruby Crystal b Flash-tube them to make this jump c Semi-reflective Mirror down, they have to d Fully-reflective Mirror release the energy e Power Supply they absorbed. To f Laser Beam release their energy, the electrons emit photons (small "packets" of light). The photon's wavelength, which dictates its color, is determined by the difference in energy between the higher-level state and the lower-level one. When one of these photons reaches another excited atom with an electron in the same higher-energy state, that atom in turn releases a photon of its own. This reaction causes the number of photons to grow extremely quickly as more and more photons hit excited atoms. Since the difference between the higher and lower-energy states is the same in all the photon producing atoms, all the photons have the same wavelength and are in-step with each other, or "coherent". This is why lasers produce beams of light that are a single color. This process is called stimulated emission, and in order for it to work effectively there must be more excited atoms in the medium than non-excited ones. We call this population inversion. The higher the number excited atoms compared to non-excited atoms, the greater the degree of population inversion. The greater the degree of population inversion, the more effectively stimulated emission works. The coherence of photons and two mirrors at opposite ends of the lasing tube give lasers their signature narrow, focused beam. A fully reflective mirror is placed at the back of the laser and a semi-reflective mirror placed at the front. Some of the photons bounce off these mirrors, but only photons that travel parallel to the lasing tube's horizontal axis remain inside the laser cavity. The semi-reflective mirror allows some of these photons to pass through, while reflecting others back to the fully-reflective mirror so the stimulated emission of photons in the tube continues. The photons that pass through the semi-reflective mirror are the intense, narrow beam of light we see produced by the laser. The technical term for this whole process is "light amplification by stimulated emission of radiation", or "laser" for short.

Compact Discs The first compact disc was made commercially available in 1982. Now billions are used worldwide every year. But how do these revolutationary storage devices work?

A compact disc is composed of a thin layer of aluminum sandwiched between two plastic ones. laser pickup

pits

The aluminum layer in the middle of a compact disc is covered in microscopic pits. To retrieve information stored on a compact disc, a low power laser beam is shined onto a semi-reflective mirror that reflects the beam onto the surface of the disc. When the laser beam hits a flat part of the disc, the beam bounces back through the semi-reflective mirror. This produces a flash of light that is read by a light sensor behind the semi-reflective mirror. When the laser beam hits a pit, the beam is scattered and not reflected. The light sensor reads the flashes of light as on-off signals. These on-off signals represent binary code, a system of counting using only O's and l's. standard

binary

10 9 8 7 6 5 4 3 2 1

0 1 0 1 100 1 0 0 0 1 1 110 0 1 1 0 1 0 1 0 0 0 1 0 1 100 0 1 0 0 1 0 0 0 0 0 0 0

Il-" 0"

the digits of binary are exponents of two

~" ~"

o<::,~",o"::>rv<f

2째 = 1 21 = 2 22 = 4 23 = 8

Each additional digits place is equal to a higher power of two

The digits places in binary are exponents of 2 in standard decimal form. So the first digit is 2째, meaning a 1 there is equal to 1 std; the second digit is 2\ so a 1 there is equal to 2 std; the third digit is 2 2 , so a 1 there is equal to 4 std, and so on. To find the value of a binary number in standard decimal form, add up all the standard decimal form values of the digits places in the binary number where there is a 1. So 0 1 lOis equal to 0 + 2 + 4 + 0, which equals 6 in standard decimal form. These sequences of pits spiral around the disc outward from the center. For the disc to be read properly, the laser must be kept in extremely precise alignment with them. This means the laser has to move in incredibly small increments to stay in sync with the disc. This is done using a tracking motor that moves the laser microscopic distances. In addition, the disc motor that rotates the CD changes the speed of rotation depending on the track it's on. In other words, to keep the laser covering the same amount of surface as it moves further away from the center of the disc, the disc is spun at different speeds. The disc motor spins the disc at speeds between 200 and 500 rotations per minute.

is for Magnetism The History of Magnets .N

The first application of the magnet was in its use in compasses. It was observed that certain materials would align themselves to point north. Because of this, the ends of magnets are now thought of as having north and south ends. There is a magnetic field that surrounds the earth, and its magnetic pull makes the needle of the compass, which is a magnet, turn to magnetic north. What we think of as the north pole is actually the location of a physical south magnetic pole; this is why a needle of a compass will point north. Earth's magnetic field pulls towards north. Georgrahical north is the axis that the earth is spinning on. The angle between magnetic north and geographical north is called the declination.

s Magnetic Fields A magnetic field is the area surrounding a magnet where it produces a magnetic force. This is shown in the first diagram below. Two like poles repel each other, and opposite poles attract. When a north and a south end are put together, the field lines produced look like the second diagram below. When two repeling ends are put together, the field lines push against each other. The field Magnets are either lines made by two opposing ends also produces a negative space where there is "hard" or "soft" no net force. This is shown by the X in the diagram below. according to how difficult they are to magnetize and how long they stay magnetized.

Scientists believe that the earth's magnetic field will completely reverse every few hundred thousand years.

Electromagnets Electromagnets refer to the creation of a magnetic field when an electrical current flows. This reaction was discovered by Oersted in 1918. If a wire is suspended above a compass that points north, the needle will not move until an electrical current is put through the wire. If the current is reversed, the compass will move in the opposite direction. This discovery was developed into Soft Iron Core . . . creating the electromagnet, which can be sWitched on and off according to whether or not there is a current flowing through the Coil wire. The strength of the electromagnet will increase if any of the following occur: I. The current in the coil increases II. The number ofturns in the coil increases III. The poles are closer together

is for Nuclear Chances are, if you're reading this book, you've already had a science class or two so likely you've come across the term 'Nuclear' before. (Or perhaps you've even heard it pronounced as "Nu-QU-Iar"). But many people throw the term around without really understanding what it means. In chemistry, we learned that all things are made up of atoms, which are the basic building blocks of matter. Atoms, as you probably know, are made of protons, neutrons, and electrons. Protons and neutrons form what scientists call the nucleus. The term 'nuclear' merely refers to anything that involves a nucleus. Nuclear reactions are changes that occur in the nuclei of atoms. These changes are important because they often create new atoms. They also generate NUCLEAR ENERGY! "But how do I know these reactions are really there?" you ask. Well, nuclear energy can be observed around us all the time whether by natural means or human produced. After all, it's been around longer than electricity or gasoline! Human Produced Reactions:

Natural Reactions:

Nuclear power plants and reactors are an alternative source of power to gasoline, which is becoming much harder to find. France gets over 75% of its energy from nuclear power.

The sun and other stars make heat and light by nuclear reactions.

Fission, Fusion, and Spontaneous Nuclear Reactions! Nuclear reactions are important because they generate nuclear energy, which can be utilized for a variety of industrial purposes. The three most common types of nuclear reactions are fission, fusion, and spontaneous reactions.

Fission A process where a large nucleus is split into two smaller daughter nuclei. This creates a substantial release of energy.

Fusion

A note about Spontaneous Reactions...

A process when two nuclei with low mass numbers are joined to form a singular heavier nucleus. This also creates a substantial release of energy.

/t's important to note here that all nuclear reactions do not occur from the processes offission or fusion. Often, changes can occur without splitting or joining nuclei.

But how do nuclear reactions relate to the real world?

Currently nuclear power plants rely on fission reactions to produce power. The Earth has limited supply of coal and oil. Nuclear power plants could still provide energy once these become scarce. They also need less fuel and produce more energy. Nuclear energy has a variety of other applications such as medical imaging, detection, and many more.

The Big Question:

radioactive dating,

radiation

Fission based power plants rely on rare uranium and plutonium as fuel, which are extremely difficult to extract.

"ls there any way to produce nuclear power more efficiently?"

mc2

Einstein's Famous Equation

Energy is equal to the mass multiplied by the speed of light squared. But what does this really mean? In the case of nuclear reactions, since the speed of light is a constant number, mass is the only thing that can change the amount of energy output in this equation. In reactions such as fission, where a nucleus is being split, the combined mass of all daughter nuclei (including the free nuetrons) is slightly less than the mass of the original nucleus. This mass deficit is a fraction of the mass of a single nuetron or proton. Infusion reactions, the nucleus created by the original nuclei has a lighter mass than the original nuclei had when their respective masses were added together. Like fission reactions, this 'missing mass' is the source of the energy release.

The Future of Nuclear Energy: FUSION POWER! The "Hydrogen Bomb" is an explosive based on the fusion of hydrogen. It utilizes an uncontrolled fusion reaction. Since the 1950s, scientists have been attempting to develop a form of

controlled fusion reactions and use the technology to produce electricity. Hypothetically, the waste from fusion power plants would be less toxic or possibly not toxic at all. Also, fusion power plants could utilize various hydrogen isotopes as fuel that can be extracted from the oceans as opposed to uranium or plutonium. Modern science is pressing forward with various ways to overcome the obstacles that stand in the way of fusion power. The main roadblock lies in the fact that the charges of hydrogen nuclei repel each

other

because

they

are

both

positive. In order for fusion to take place, two nuclei must touch. Currently, three methods are being studied to achieve this. The most promising method is magnetic confinement, also known as "The Tokamak Approach."

Scientists discovered that high temperatures are needed in order for the nuclei to touch and fusion reactions to occur. Because heat is generated by kinetic energy, this means that the nuclei must also move very fast. The Tokamak was a device invented in the 1950s by Soviet physicists that utilized an extremely powerful magnetic force in order to contain the matter so it did not come into physical contact with the walls. If the nuclei touched the walls, energy would be lost making it impossible to initiate fusion.

Radiation Radiation is a topic central to nuclear physics. An extremely broad topic, radiation generally refers to any type of energy (such as light) that travels through space. Radiation itself is divided into two types: non-ionizing and ionizing radiation. Non-ionizing radiation is the type people are most familiar with, though usually by other names. The term encompasses radio waves, microwaves, as well as visible light. â&#x20AC;˘

lIIIIIia

Conversely, ionizing radiation is the type involved in nuclear reactions like radioactive decay and fission. Ionizing radiation is capable of stripping electrons from an atom, turning it into an ions, due to the amount of energy its waves contain. Consequently, ionizing radiation poses a medical risk becaue if the molecules in your DNA are ionized, they will be damaged, and your cells may mutate. That process is how this type of radiation causes cancer.

Isotopes One cannot understand nuclear reactions, and consequently, ionizing radiation, without learning about isotopes. The term isotope refers to the different forms of a specific element. Specifica lIy, the nu m ber of protons determ ine the element of an atom, the number of neutrons determine the isotope, and the number of electrons (compared to the number of protons) determines the charge. Take for example, Hydrogen: its atomic structure consists of a single proton, and anywhere from zero to a dozen neutrons. Any atom with one proton will be an atom of hydrogen, but the different isotopes of it contain different numbers of neutrons. Below are the isotopes for a few well known elements. Only a few are shown; Hydrogen has seven different isotopes, while Uranium has over thirty

Uranium

Hydrogen lH - Protium 1 Proton o Neutrons The most common isotope of hydrogen, making up 99.98% of hydrogen on Earth. It is a stable isotope.

2H - Deuterium 1 Proton 1 Neutron The second most common isotope of hydrogen, making up <.02% of hydrogen on Earth. It is a stable isotope.

3H - Tritium 1 Proton 2 Neutrons The least common isotope of hydrogen, found only in trace amounts on Earth. It is unstable, and undergoes beta minus decay with a half life of "'12 years.

235

. Uranium

238Uranium

239Uranium

92 Protons 143 Neutrons

92 Protons 146 Neutrons

92 Protons 147 Neutrons

The second most common isotope of uranium. Undergoes Alpha Decay and has a half-life of 7.10 8 years.

The most common isotope of Uranium found on Earth. It Undergoes Alpha decay and has a half-life of roughly 4.5.104 years.

Naturally found only in trace amounts. Undergoes Beta decay; has a half-life of 24 minutes.

Stability, Decay and Emitters An atom's stability is dependant on the various forces at work within them. These forces are determined by the number of protons and neutrons, and the ratio between the two. As a result, different isotopes of the same element can undergo different types of decay. In Hydrogen we see that protium PH) is a stable atom with 1 proton and 0 neutrons, whereas tritium is unstable with 1 proton and 2 neutrons. In order to reach stable states, atoms like tritium undergo decay. There are three types of radioactive decay, known as Alpha decay, Beta decay, and Gamma decay. Each type of decay is a different, but all types bring atoms towards a more stable ex Decay state. Atoms that perform these types of decay are called emitters, because during radioactive decay, they emit particles. Those particles vary depending rx Particle on the types of decay the atoms undergo. The emit+ ted particles travel in "waves", named after the type of decay that produces them. 4Helium [2 Protons, 2 Neutrons]

Alpha Decay Alpha decay frequently occurs in larger atoms with too many protons relative to their number of neutrons. During Alpha decay, the atom emits a 4He (Helium-4) atom, called an alpha particle. The atom loses two protons in this emission, subsequently becoming a different element. Alpha waves are frequently stopped by air, due to the size of their particles.

Beta Decay Beta decay occurs in a nuclei with either too many neutrons or too many protons. There are two types: Beta minus and Beta plus. Beta minus transforms a neutron into a proton, and emits and electron and an anti-neutrino. Beta plus transforms a proton into a neutron, and emites a positron (an anti-electron) and a neutrino. Beta Waves travel through air but are stopped by materials like plastic, as well as human flesh.

Gamma Decay

238Uranium

234Thorium

[92 Protons, 146 Neutrons]

[90 Protons, 144 Neutrons]

Decay ~

3Hydrogen

3Helium

[1 Proton, 2 Neutrons]

[2 Protons, 1 Neutron]

Particles

â&#x20AC;˘

Electron

â&#x20AC;˘

Anti-Neutrino

~+ Decay ~

Particles Positron

+ o Neutrino llCarbon

llBoron

[6 Protons, 5 Neutron]

[5 Protons, 6 Neutrons]

Gamma decay is unique in that it simply involves an atom 'descending' from a higher energy level to a lower one. In Gamma decay, an atom maintains all its protons and neutrons. However, it emits energy in the form of dense packets of light called "photons". :.:.:.:~ Gamma waves travel through air, flesh, and even ,lead. Of the three types of ionizing radiation, gamma I I) \ waves are the most dangerous because of that fact; Energized they are the most likely to interact with your DNA.

y Decay y Particle

+ \\

3Helium

[2 Protons, 1 Neutron]

3Helium [2 Proton, 1 Neutron)

Photon

Carbon-14 Carbon-14 is a carbon isotope. A normal carbon atom has a nucleus that consists of 6 protons and 6 neutrons. An isotope is an atom that has a different atomic mass than the usual atom. In this case, the atomic mass is 14. The carbon-14 nucleus contains 8 neutrons instead of 6 neutrons, and this makes the isotope radioactive.

Creation of C-14

Neutron - . Proton -

How is C-14 made and put into the environment?

ln +14N -714 C + lH Carbon-14 is made at very high altitudes (9-15 km). Neutrons playa vital role in C-14 creation. Extremely high energy cosmic rays from outer space collide with gas molecules in the upper atmosphere. Occasionally, this causes a neutron to be ejected. Sometimes, this neutron collides with a nitrogen atom. Once the nitrogen is hit, a proton is released while the neutron is absorbed, forming Carbon-14.

,{ Cosmic rays collide with "/ Nitrogen in the upper troposphere Neutrons make up approximately 90% of cosmic rays H d ~

/v.

.---i~~

yrogen

The neutron knocks a proton out of the Nitrogen

Which makes C-14 isotopes Carbon Dioxide can be absorbed in by trees and other plants

Radioactive Dating

Plants are eaten by herbivores

One unique use of C-14 is radioactive dating. Carbon-14 dating requires a basic knowledge of radioactive decay. Radioactive material, such as Carbon-14, decays at a rate called a half-life. A half-life is measured in a specific amount of time. Each radioactive material has its own unique half life.

Humans eat both plants and animals

~ ~

In one half life, an organism gives off half of the radioactive material. For Carbon-14, the half life is

approximately 5,700 years. This means that it takes a non-living organism about 5,700 years to give off half the amount of the C-14 it has. Below is an example of a Pterodactyl. The amount of Carbon-14 fluctuates throughout its life, but decays once it's dead. Rate of C-14 Deca

C-14 Amount -

1/1

LLION

YEARS

PRESENT

®jS for Optics Optics refers to how light propogates through different types of matter. Optics has been studied since the Egyptians created lenses from a polished crystal. The study of optics continued with the Romans as they filled glass vases with water to create lenses. Now optics includes the use of lenses, mirrors, prisms, and fiber optics.

Convex Lens

Concave Lens

The convex lens is often used to look more closely at The concave lens is often used to make larger objects smaller objects, such as coins or stamps. Seen above is seem smaller. Seen above is a double concave lens. a double convex lens. After entering the lens, the light After entering the lens, rays of light bend outward, or rays bend inward, or refract, focusing the light on one diverge, spreading the light outwards. Note how the point. Note how the light rays that enter farther away light rays that enter farther away from the axis bend from the axis bend inwards more. As seen in the outwards more. As seen the in the diagram below, a diagram below, a convex lens makes the lightbulb concave lens makes the lightbulb appear smaller when appear larger when projected onto a screen. Convex seen. Concave lenses are used to correct near-sighted lenses are used to correct far-sighted vision. vision.

-Object

Object Projected Image

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Virtual Image

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The Telescope Telescopes allow an object to appear larger without inverting the image. To measure the amount of magnification in a telescope, divide the distance from the center of the objective lens to the focal point, F0, by the distance from the focal length to the eyepiece, Fe .

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Thin Lens Equation The thin lens equation is used to determine at what distance rays of light will intersect after going through a I ns. This equation is able to ca late the size and type of the pres ription gl~ses you need. The distance from the obJ ~the~~s is u. The distance from the object to t~ . Ji?~cfel(image is v. The focal length of th, I~ . is f~~onvex lens has a positive focal concave lens has a negative focalleng

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Mirrors If\J! llOl2 \

Concave Mirrors are used to direct light. An ideal shape of a concave mirror is a parabola, which causes all of the light rays produced by the bulb to go in one direction. Concave mirrors can be seen in flashlights and car headlights.

Mirrors are surfaces that reflect light. The most familiar mirror is called the plane mirror, which is a mirror that is completely flat. Mirrors that are curved can diminish or distort images, as seen in fun houses. Mirrors are used in everything from bathrooms to cameras to industrial machinery.

Convex Mirrors are used to spread light. The ideal shape of the convex mirror is a a half of a sphere, which causes all of the light rays produced by the bulb to go in all different directions. Convex mirrors can be seen in rear-view mirrors in vehicles.

Mirrors that are angled can also be used to redirect light and images, as seen in a periscope. Notice how the orientation of the image is kept the same after it has been passed through two mirrors. Had only

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one mirror been used, the image would have been seen as a "mirror image."

Above is an example of how prisms can be used. The image is flipped downwards (vertically) then across (horizontally). Once the image has gone through both prisms, the processed image is an exact opposite of the actual image. Binoculars are very much like telescopes. However, telescopes require a lot of length to be effective. Binoculars are able to be short because prisms force the image to travel the shorter distance multiple times. As seen above, the tree image travels the same distance three times because of the prisms.

Fiber Optics Fiber optics were hailed as the future of communications cablesduringthe 1990s. Offeringan extremelyhigh bandwidth, fiber optics have gradually replaced the more commonplace coaxial cable. Now, they're found in various communications networks. Although coaxial cables can carry high bandwidth signals, these signals are lost easily over long distances. When transferring high bandwidth data over long distances (for instance, from Los Angeles to New York), fiber optic cables are preferable. Fiber optic cables, which transfer data with light, require amplifiers for longer transmission distances. In past long-haul systems, the light signal had to be converted into an electrical signal before amplification could happen. Recently, strides towards all-optic systems have been made such as using semiconductor optical amplifiers (SOAs) or eridium doped fiber amplifiers (EDFAs). These amplifiers can boost the signal strength while keeping it in its optical form, making it unnecessary to occasionally convert from optical to electrical and back. Total internal reflection is what allows light to travel through the fiber. When light passes from one medium into another medium that has a lower index of refraction, the light will bend away (the green line in the diagram at the right) from an imaginary line that is perpendicular to . the line between the two media (the orange in the ~XI~ diagram on the right). At a certain angle, known as the critical angle, instead of refracting, the light will instead travel along the surface between the two media (the blue line in the Cladding diagram on the right). At an angle greater than the critical angle, light is reflected instead of refracted (the red line in the diagram on the right), and travels through fiber optic cable by being reflected back and forth. In the cable, the cladding absorbs no light from the core, so light can travel great distances. Light is really only lost due to impurities in the glass, so optic cables cause much less signal loss per kilometer. TAT-12 and TAT-13 were the first transatlantic fiber optic cables and were in operation from 1996 to 2008. They were notable for the use of a self-healing ring structure. If a problem is detected, traffic within the system can be redirected around the problem in less than 300 milliseconds--this is why the structure is called "self-healing." In order to lay fiber optic cables down along the ocean floor, large ships that can support the weight of the large spools of cable are needed. The cable on these spools are usually around 69 millimeters in diameter and weigh around 10 kilograms per meter of cable. This weight and diameter is caused layers of by the necessity to protect the cables from underwater conditions. There are several sheathing used in the underwater cables such as the copper or aluminum tubing aluminum water barriers.

is for potential energy

Potential energy, specifically gravitational potential energy, is defined as the energy stored by an object because of its position. When held at a low height from the ground, the potential energy is low. When held at a higher height from the ground, the potential energy increases. This occurs because of the equation:

PotentialEnergy = mass x gravity x height

Potential Energy Equation Explained ...

Potential Energy in Action ...

Potential Energy is equivalent to Work Mass is measured in kilograms Gravity is measured in meters per second squared Height is measured in meters

In this example, the red rubber ball, held above the ground, has stored potential energy.

The equation including the product of mass, gravity, and height was derived from a series of known equations. Beginning with the equation of force:

Force = mass x acceleration

We know gravity, which is measured in meters per second squared, is acceleration, therefore:

When the ball is dropped, potential energy is gradually converted to kinetic energy as the velocity increases.

Force = mass x gravity The equation for Work is:

War k = Force x distance By isolating force in the work equation, we'll notice:

Force = Work -7- distance

Then by setting the two force equations equal to each other:

mass x gravity = Work -7- distance We can replace distance with height because it is the distance:

mass x gravity = Work -7- height After rearranging the equation, the potential energy equation is complete:

Work = mass x gravity x height W=mgh

Did you know... There is no actual zero point of potential energy. It seems logical to believe that when the item is on the ground its potential energy is zero but it's still possible to dig deeper into the ground, thus allowing a negative potential energy.

Elastic Potential Energy...

The potential energy of a manipulated elastic object is known as elastic potential energy:

ElasticPotentialEnergy

2,kx 2

The constant of the spring is defined by k. The stretch or compression relative to its dormant position is defined by x. Hooke's Law is used to determine the force required to compress or stretch a spring: A spring is a good example of potential energy. Once pulled apart, there is a force that resists the pull by compressing the spring. The longer it is stretched, the more elastic potential energy it has.

F=kx

Potential Energy Examples...

If a 1 kilogram ball is dropped from the top of a 6 meter building, how much potential energy does the ball have halfway to the ground?

mass x gravity x height

lkg x 9.82" x 3m

29.4kgm

6 meters

29.4J

When the 1 kilogram ball hits the ground, it compresses .027 m. What is the force of the constant of the ball?

spring constant x spring displacement F

mass x gravity

lkg x 9.82" s

F 9.8N

9.8N

spring constant x spring displacement 9.8N

spring constant x .027m

. sprzng constant

N 362.963m

is for Quantum Mechanics History Quantum mechanics is a branch of science that studies the behavior of matter and energy at the atomic and sub-atomic level. Quantum mechanics attempts to quantify specific properties, such as position and momentum, of particles (atoms, electrons, neutrons, etc.) These microscopic entities behave differently than normal everyday objects because they exhibit the properties of both a wave and a particle. Quantum mechanics describes these objects mathematically but is not descriptive about the mechanics involved. Light is one example of particle-wave duality. In the past, the true nature of light was always a mystery. Was it a particle or a wave? Today, scientists have realized that light shows particle or wave type characteristics depending on the experiment. In 1905, Albert Einstein explained the photoelectric effect. He found that photons (the particles that make up light) of a certain energy level release electrons from negatively charged metals. Because the amount of electrons A nucleus model of a released from the metal depends on the energy contained in single photons, nitrogen atom Einstein determined that light was particle-like. Einstein believed this to be true because red light could not release any electrons from negatively charged metals while blue light could. He reasoned that wheter electrons were released or not came down to the frequency of the light. Higher frequencies of light have photons that contain more individual energy than photons of lower frequencies. Only the high frequency photons have enough energy to free an electron. At around the same time that Einstein explained the photoelectric effect, Neils Bohr was creating a model for electron orbitals around a nucleus. He claimed the movement of matter at the subatomic level was instantaneous and not continuous. In classical physics, the electron is described as continuously accelerating in a curved path towards the nucleus, losing energy while doing so, and thus releasing photons in the process. However, if this were true then the electron would eventually accelerate right into the nucleus. This obviously does not happen. Electrons do not run into their nuclei. Instead, quantum mechanics describes the subatomic transfer of energy much differently from that of classical physics. In this explanation, energy is believed to exist in very small discrete units called quanta. Energy can only be transferred in whole values of those quanta units, so when an electron moves into a lower energy state, it "teleports" into that specific orbital. There is no continuous movement of that electron because it all happens instantaneously. Bohr's radical claim stated that electrons could only exist in those specific orbitals and nowhere in between.

The Copenhagen Interpretation Neils Bohr most famous contribution to quantum mechanics was his Copenhagen Interpretation. He claimed that all activity at the quantum level can be described by waves. In fact, he claimed that anything at the quantum level does not physically exist. Everything is a wave of probability, a probablity of existing at a certain spot in space. Only when a measurement is made on the particle does the wave "collapse" and thus forces the particle to reveal itself.

Schrodinger's Cat In 1835, Edwin Schrodinger developed his famous thought experiment known as Schrodinger's Cat. In the experiment, he placed his theoretical cat in a box accompanied by a bit of radioactive material and a Geiger counter. A Geiger counter is a measuring device used for detecting radiation. The counter was rigged so that if it detected radiation it would trigger a hammer to break a flask of poison and thus kill the cat. The radioactive material had a 50/50 chance of decaying after an hour.

Schrodinger's thought experiment emphasized the unbelievable nature Copenhagen Interpretation was correct, then the cat should be both obviously does not make sense. How can a cat be both alive and collapse the wave function, meaning that the wave function of the state to be, either dead or alive. Schrodinger was trying to highlight make sense. Shouldn't the cat have been alive or dead before an room? What qualifies as a conscious observer? He brought up further prove how physics at the quantum level disagrees with scale. These notions got scientists like Bohr and Einstein arguing over the true nature of the subatomic world. Bohr challenged our understanding of reality by stating that subatomic particles truly did exist as waves of probabilities. Einstein protested against that with his famous quote: "Quantum mechanics is certainly imposing. But an inner voice tells me that it is not yet the real thing... I, at any rate, am convinced that He does not throw dice." Einstein's life was devoted towards trying to unify quantum theory and general relativity. He did not succeed and quantum theory's erratic nature, to this day, seems to conflict with our understanding of reality.

of quantum mechanics. If the partially alive and dead. This dead? An observer should cat would "choose" which the fact that this does not observer came into the these profound questions to physics at a much greater

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K is for Radio

Radio is a simple technology that is present in everyday life. From cell phones to baby monitors to satellite communications, radios come in many different forms. Radio signals are made up of two superimposed waves: A high frequency carrier wave plus a lower frequency wave which carries the information being sent. Regular sound waves travel by vibrating air molecules but these waves never travel far because the energy quickly disperses. Radio waves are electromagnetic disturbances that can pass through buildings, around mountains, and even through space. By using electromagnetic radiation we can carry audio waves over vastly increased distances. AM &FM AM- Amplitude Modulation

FM- Frequency Modulation

AM refers to a way of encoding information onto radio frequency (RF) waves. The amplitude of the radio frequency wave changes to match the audio signal. It is the simplest way of encoding information and also the easiest to decode. Unfortunately, interference is a very common problem. This can be caused by anything from a car starting to noise from electric appliances. Consequently, AM radio typically has a lot of static. FM is another type of radio transmission. In FM, the frequency of the carrier wave changes with the audio signal. Typically, FM has little interference and static noise does not alter the radio wave frequency as much as it alters the amplitude. This means FM has better sound reproduction in comparison to AM. FM radio is also broadcast on a higher frequency carrier wave which allows more information to be encoded. This means a stereo signal can be sent over FM.

Amplitude Modulation

((( ))) Amplitude Modulated Wave

Recorded. Sound

Transmitter The sound recorded from the microphone has two parts; the audio signal, which is the actual sound, and the radio frequency, or carrier wave. Together, the two produce an amplitude modulated wave that can be transmitted. The RF signal is the audio signal and the amplitude of the signal changes in relation to the sound being produced.

Baby Monitors Modulation Type: AM Modulation Frequency: 49 MHz Transmitter power: 1/4 watt

Oh no! Baby has woken up and cries out to her Mommy and Daddy. Luckily they set up a monitor in Baby's room. Now they are able to hear her cries through the receiver with them in the kitchen.

A baby monitor is a simple type of radio, so it has a transmitter and a receiver. Once the audio has been encoded on the carrier waves the RF signal is amplified and passed over to the transmitting antenna. The electrons in the antenna move up and down in relation to the signal creating an electro magnetic field. This electromagnetic field radiates outwards from the antenna carrying the radio signal with it. When it gets to the receiver it causes the electrons in the antenna to move in the same manner. This creates a tiny electrical signal. The signal has a signature frequency. The tuning electronics on the receiver filter out anything other than this frequency and decodes the audio frequency. A baby monitor with a small power supply can typically transmit information up to 200 ft. A radio station typically uses 50-100 watts to transmit information for miles. A larger power source allows the transmitter to send information further. The specific frequency also effects the distance the information can be sent.

CDMA- Code Division Multiple Access CDMA is a more complex form of radio that is commonly used in modern wireless technologies, such as cell phones. Instead of assigning each user a specific frequency per wireless device, CDMA uses multiple and varied frequencies to transmit the audio signals. The reason for doing this is if one frequency drops out or becomes crammed, the connection is not completely lost. All of the 3G technologies today are were created from CDMA. During World War II, CDMA was used by the English so the German's could not jam their transmissions and decode their messages. Now, Qualcomm commercialized the technology and holds all patents.

is for Solar SOLAR ENERGY The sun is a star at the center of our solar system. It accounts for

99.9% of the entire solar systems mass. In the form of sunlight, the suns energy supports almost all life on Earth. The sun is largely responsible for the weather and climate on earth as well. Essentially, almost all energy

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Solar energy is the radiant light and heat that the sun emits. Humans have been harnessing energy from the sun since ancient times. The sun radiates an immense amount of energy. On a sunny day, the sun shines approximately 1,000 watts of solar energy per square meter of the Earths Surface. From the surface of the sun, solar energy takes about 8 minutes, traveling 186,000 miles to per second, to reach the Earth.

on earth leads back to the sun. For example, for humans to stay alive, they need to consume food. That food would not have been able to grow if it had not been exposed to sunlight. Plants use

photosynthesis by first trapping light through their leaves. They then convert that sunlight into energy that they use to create food for themselves.

SOLAR PANELS

~~ 0( - - - - - - - - , The world currrently extracts a lot of energy from limited I natural resources. In an effort to move away from this, ~ ,ollIIIIII-"~ Battery scientists are exploring the idea that the earth could ~:me day Inverter Or System run on free electricity from the sun. Photovoltalc Cells 19' Produces DC are an important part of this "solar revolution" because they Converts DC power to AC (alternating current) (direct current) Power able to absorb light from the sun through semiconductors which Power convert sunlight into energy.

SEMICONDUCTORS

The semiconductor is split into two sides. Both are made of silicon but the pink side is infused with Boron (the p-type layer), and the blue is infused with phosphorous (the n-type layer). Sunlight hits the p-type layer and knocks electons from the atoms inside, leaving a hole on the atom and giving it a positive charge. The loose electrons are now inside the n-type layer but are attracted to the p-type layer, because of the positively charged atoms there. They are then forced to complete a circuit, which provides energy to the load that the circuit is connected to.

is for superconductors Superconductors are materials that conduct electricity without resistance or loss. This means that an electrical current can flow in a loop of superconducting wire, making it the closest thing to a perpetual motion machine that can occur. Superconductivity is referred to as a "macroscopic quantum phenomenon". This is a process that occurs due to the quantum nature of atoms. We can see the effect on a macroscopic level, that means we can see the effect with the naked eye.

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The electrical resistance of an element increases along the T line. As the element warms up, the atoms in the element get more excited and bounce around. This bouncing makes it more difficult to conduct electricity. When an element reaches its superconducting critical temperature, its resistance 3

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immediately drops to zero. When we look at the T line we can see that resistance would eventually reach zero, at the zero Kelvin mark. Superconductive materials will reach zero resistivity at a certain temperature. The graph shows that this example reaches zero resistivity at 0.6 Kelvin. Different materials have different superconductive temperatures. Some materials, like wood, are not affected by magnetic fields. ResiS1:ance Other materials, like ferrous metals, when exposed to a magnetic field create a field .8 aligned with the original field. These .6 paramagnetic materials absorb the field and become magnetized themselves. If a piece of .If iron gets close to a magnet the field it creates causes an attractive force. We see this effect as

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When a magnet gets close to a superconductor its magnetic field induces a current in the ~l~ superconductor. This induced current causes a __..~ magnetic field to be created, which is a perfect mirror of the magnet's field. This is called the Meissner Effect. The consequence of this is that the two fields repel. When a superconductor is placed above a permanent magnet this repelling causes the superconductor to "0 .. float. Continued research into superconductors TetnPer~.,. could lead to materials with very high v~Ure

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~ temperature conducting materials \ \ ~ ~~ can. be. used in man~ different OfA in CI ) )1)re-Crltlca\ applications. A potential use for JI r superconducting critical temperatures. These hight (

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magnetic tracks. The Meisner Effect could allow the train to levitate without using huge amounts of power.

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Tis for Thermodynamics Thermodynamics is the study of the relationship between heat and mechanical energy (a type of work), and the process by which one transforms into the other. The laws that are associated with thermodynamics allow us to understand the properties of heat-work interaction. KE

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When kinetic energy (KE) is transferred into heat, we can think of this process as coherent, regular motion as being randomized. The molecular energy changes from a neat, "ordered" system (with all molecules moving in the same direction) to being "disordered". In physics, this disorder can be measured and is called entropy.

Ludwig Boltzmann was an Austrian physicist who worked in the fields of statistical thermodynamics and mechanics. However, long before Boltzmann a German physicist named Rudolf Clausius originated the concept of entropy. During the 1850's-60's Clausius questioned the way in which heat could be used when work is done. ,...-------....., Here, NS represents entropy, Q represents the amount of heat absorbed by a system in an isothermal and reversible process in which the system goes from one state to another, and T is the absolute temperature at which the process is occurring. All in all, this equation represents the overall change in entropy based on the temperature ' - - - - - - - - - - ' of the system.

Q T

Isothermal and Adiabetic Processes An isothermal process is a change in which the temperature of a system stays constant. This typically occurs when a system is in contact with an outside thermal reservoir (heat bath), and the change occurs slowly enough to allow the system to continually adjust to the temperature of the reservoir through heat exchange. When a system exchanges no heat with its surroundings (Q = zero) the process is considered adiabetic. This typically occurs as an explosion, and happens very quickly while an isothermal process takes longer. Reversible Process In thermodynamics, a reversible process (or reversible cycle if the process is cyclic) is a process that can be "reversed" by means of changes in some property of the system without loss of energy. Due to these changes, the system is at rest throughout the entire process. Since it would take an infinite amount of time for the process to finish, perfectly reversible processes are impossible. In a reversible process, the system and its surroundings will be exactly the same after each cycle. Absolute Temperature Thermodynamic temperature is the absolute measure of temperature and is one of the principal aspects of thermodynamics. Thermodynamic temperature is an absolute scale, because it is the measure of the most important property underlying temperature: its null or zero point: absolute zero. Absolute zero is the temperature at which the particle constituents of matter have minimal motion and can be no colder. Note that this portion ties into the concept of absolute zero.

The Laws of Thermodynamics Zeroth Law When two objects are in contact with each other, they eventually reach equilibrium in their temperatures First Law Energy can only change in forms, it cannot be created or destroyed, only transferred Second Law Entropy increases to reach thermodynamic equilibrium when isolation between two systems is broken, allowing them to exchange energy. There is no energy as heat without a temperature difference Third Law Absolute zero (zero Kelvin) can never be achieved

Q-Te

This equation shows the change in entropy as a result of temperature. Here, Q represents change. T(h) represents the hot temperature and T(c) represents the cold temperature. The first term will always be bigger than the second. This means that entropy is always increasing. Entropy can only decrease as a result of a manmade force. Even then, the small or medium increase in entropy is still not larger than the increase in entropy. The entropy of a single object can go up or down, it is the entropy of the universe that is always increasing!

Examples of Entropy An air conditioner cools the air in a room, reducing the entropy of the air. However, the heat expelled by the air conditioning will always make a bigger contribution to the entropy of the environment than the decrease of the entropy of the air (heat must be expelled in order to produce cold). So, even though the entropy of the air is experiencing a slight decrease in entropy, the increase is still larger in universal terms.

Disorder can also increase without heat flow! Atoms are bouncing around inside a tied-off balloon. If you pop the balloon, the atoms are no longer confined to a region, but spread throughout the atmosphere.

is for Ultrasound Sound Waves: High and low pressure pulses traveling through a medium that can pass through solids, liquids and gasses. High pressure Low pressure

---+ ---+

compression = particles are squeezed together rarefaction = particles are spread apart

rarefaction

compression

Frequency: The number of pulses transmitted every second.

P/\f\f\f\/\ V\JVVvV

High frequency

fL\L\L\ V V V V

Low frequency

Wavelength: The distance the wave travels between pulses.

Wave Equation: Calculates the velocity of a sound wave.

V==fÂˇA v= velocity

f= frequency

A.=wavelength

Humans can hear from 20 Hz to 20,000 Hz. Ultrasound operates at frequency one thousand times greater than this.

Ultrasound: High frequency sound waves ranging from 1 MHz to 20MHz with wavelengths of 1 to 2 millimeters.

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The speaker is emitting sound waves, which bounce off the object creating an echo, which can be analyzed so one can identify the object.

When the sound waves encounter a border between two tissues (stomach and fetus) the sound waves bounce off and create and echo which is analyzed by a computer and transformed into moving pictures.

Interal Rectus Muscle

is for Visif)ll

Lens

Vitreous Body

The human eye allows us to see our surroundings by Sclera collecting light and converting it to electrical signals that are passed to the brain. The outer layers of the eye comprise the Pupil-i/t-of---,..... I cornea which provides most of the focusing for the eye and Iris the pupil which limits the amount of light entering the eye. Our eyes work differently from a camera where the glass lens Conjunctrua moves forwards and backwards to focus an image. The lens inside the eye remains at a fixed distance and instead changes shape Ciliary in order to focus. The lens is linked to two muscles called ciliary Body Medial Rectus Muscle muscles. These stretch or compress the lens depending on the distance to the object. A thinner lens focuses on distant objects, a fatter lens on things that are closer. Another important part of the eye is the retina, where a focused image is converted to electrical signals. The retina is made up of 120 million rods and 6 million cones that assist in adjusting in the dark or taking in as much light in order to see certain objects and colors. These rods and cones are connected to more than 1 million neural pathways that collect together to form what we know as the optic nerve. Since the human eyes are 2 inches apart, this gives them two different views on their surroundings. This is called Binocular Vision. The brain is able to interpret the two slightly different viewpoints and gain a sense of depth and distance. View-Masters use binocular vision to create a three dimensional image. Once the eyes are placed over the two holes each eye sees an image of a scene taken from a slightly different viewpoint, just as our eyes would see if we were really there. Using two such images to provide stereoscopic pictures is not new the technique was first used in 1840, and was common in Victorian times. Birds can have Binocular Vision and Monocular Vision - eyes on the side of their heads view a single side each, but the visual fields overlap directly in front of the bird. The binocular vision allows birds to judge depth and distance of their prey, while the monocular vision to the side gives a wide angle of view. This allows the birds to spot predators and prey easily. Hawks have around 1 million visual cells that cover each square millimeter of their fovea. This generates a crisp, un-blurred image of a small object. Owls have eyes set on the front of their heads, therefore giving them stereoscopic vision that helps judge distance. The only difference between these eyes and the hawks is that owls don't contain as many rods. So they are to an extent, color blind. 3D Viewing tricks the mind into producing two different images, which creates the illusion of three dimensions. One eye sees a red version of the image, and one sees either a blue or green version of the image. Humans have binocular vision, which means the brain will merge the two versions of the image to create one 3D perception. However, because of the color filters, 3D film lacks the quality of 2D color film and pictures.

Energy & Power

The Joule & the Calorie

Energy is defined as the ability to do work, whereas Power is the rate at which work is done:

The Joule is the basic measurement of energy. 1 Joule is approximately the energy needed to raise a small apple 1 meter. A Calorie is also a unit of energy.

Power

Energy Time

= ---

So to do a given amount of work, you can either operate at a high power for a short time or a low power for a long time. For example: an explosion may convert a certain amount of chemical energy to heat in a fraction of a second, which means it is relatively powerful; when you run up and down stairs you are also converting chemical energy (from the food you eat) into heat, but at a much lower rate. Power is most commonly measured in Watts (1 Joule per Second (kW) which is simply 1000 Watts.)

1 Calorie

4,200 Joules

The Human body requires 2,000 calories or SAOO,OOO Joules of energy per day.

The Watt The Watt is the most common measurement of power.

1 Watt = 1 Joule per second A Watt hour is a measure of energy equivilentto 3600 Joules, because it is the amount of energy consumed when one Watt is used over an hour (1 Joule per second times 3,600 seconds). The kiloWatt-hour (kWhL kilo meaning 1,000, is 1,000 Watt-hours or 3,600,000 Joules. This is the energy you would need to run a 1,000 Watt stove for an hour. The kWh is the unit Half a pound of dynamite contains approximately 150 used when you pay your electricity bill. A kWh Calories of chemical energy, about the same amount of typically costs about 15 cents. energy that is in a cupcake. When dynamite explodes the bonds between the atoms rearrange and release energy Usinga 60 watt light bulb for one hour consumes extremely quickly. This rapid release of energy gives the 0.06 kilowatt hours of electricity. Using a 60 watt explosion a high power, even though the energy involved light bulb for one thousand hours consumes 60 is fairly small. kilowatt hours of electricity. A 155 pound man uses the same amount of energy to If a 60 watt light bulb is on all day for one climb up stairs for an hour as used in an explosion of half week, the energy used is given by: a pound of dynamite. Power is work done determined by the rate in which it is done. = x x ~

Energy 0.06 24 7 10 kWh

At 15 cents per kWh that's only one dollar When a person consumes a cupcake, the Calories and fiftey cents! contained in it are broken down by the body, releasing energy. That energy allows the human body to perform the basic functions required for life, including movement. Utilizing the energy, our bodies can perform the work through muscle contraction. The recommended daily Calorie consumption for a human is 2,000 Calories. These Calories are matabolized by the body and provide the person with the energy needed to do work throughout the day.

Gaspard Gustave Coriolis . (1792-1843) Introduced the concept of work. He defined work as the transfer of energy acting through distance.

is for Work

Work is defined as the transfer of energy caused by a force acting though a distance. To solve for work, you need to know the force being exerted upon an object as well as the displacement the object moves whilst the force is acting. Once the force ceases to act, there is no further work done on the object, even though the object may continue to move. To find how much work is being done, you multiply the force and displacement together. The equation for work is therefore W = F . d If the force is not great enough to move the object, then the amount of work done on the object is zero as the displacement is zero. â&#x20AC;˘

Solving for Work If the girl to the right pushes on a 0.7 kg ball with a force of 55 Newtons, it will accelerate. If her hand is in contact with the ball over a 0.3 meter distance, we can find the amout of work the girl has done on the ball using the equation for work: Start off by using the work formula

W=FÂˇd W

55N

16.5J

O. 3m

Plug in the given values. F is the applied force, and d is the displacement of the object The total amount of work is 16.5 Joules

The ball then travels in a parabolic path, landing on the ground 3.5 meters away, and 1.8 meters below the girls hands. How much work is done on the ball in flight? Keep in mind that the force is now different. Although the girl is doing no work, it doesn't mean that no work is done. Gravity acts and gives a force given by F = m . 9 making The man pulls on the pulley with a the force 6.8 Newtons. force greater than the weight of the W=FÂˇd block (100 Newtons). The block will Notice the distance is the vertical displacement rise and the man will be doing work W = 6.8K x 1.8m of the ball NOT the full trajectory on the block.

Work in a Pulley

12.24J

The total amount of work is 12.24 Joules

When Work is Zero If either force or distance is absent from the equation, work will equal zero meaning no work will be done. The man to the left pushes against a wall applying a strong force. The wall is not moving and so the displacement is zero. The work he is doing on the wall is therefore zero. If a 2 ton truck were coasting down a level street maintaing a constant speed, work done is again zero. Although there are very large forces acting on the truck (gravity causes a huge downward force, and the reaction from the road provides another force acting upwards) none of these forces act in the direction of the dispacement, which is hoizontal. Since the horizontal force component is zero, work is zero.

is for X-Rays

When X-Rays are passing through matter, some of the energy packets known as "photons" interact with the particles of the object and the energy is absorbed (a process known as attenuation). Other photons pass through the matter without interacting with any particles. How many photons that are able to pass through the object is determined by the its energy and by the atomic number, density and thickness of the object. The more dense a material is, the more likely it is that the photons will be absorbed by it. That is why it is easier for X-Rays to pass through lighter atoms like the ones that make up your flesh and harder for them to pass through heavier atoms like the ones that make up your bones. The most commonly used method of detecting X-Rays is with photographic film. Because X-Rays are very similar to visible light rays, they both cause film to be exposed. However, the film used for X-Rays is often more responsive to X-Rays' wavelength. Another method, which is becoming much more common is digitally, the same Attenuation process in which digital cameras ~ (Interactions) work.

â&#x20AC;˘

The image on the right shows how the photons of an X-Ray are absorbed when they pass through an object. The amount absorbed depends on the object's thickness, density, and atomic number.

Thickness

~DenistY

Atomic Number(z)

It is possible for the energy of X-Rays to damage some of your body's cells. Although it is very rare, some cells may receive genetic damage and even turn cancerous. Reproductive cells are at higher risk than other cells. Even though you are much more likely to have cell damage from natural radiation, you should try to keep your exposure to X-Rays to a minimum.

The photo to the left shows a hand that has been damaged by high X-Ray exposure. 300 - 500 rem Erythema (skin reddening) 300 - 500 rem Temporary hair loss 700 rem Permanent hair loss 1000 rem Transepidermal injury (skin burns) 2000 - 3000 rem Dermal radionecrosis (tissue death)

Type of Radiaton Wavelength (m)

Radio

Microwave

Infrared

103

10-'

10-5

10'

108

10"

Visible Ultraviolet X-Ray Gamma-Ray .5x10-8 10-8 10-10 10-"

Frequency (Hz)

1015

10 '6

1018

10'0

The image above shows X-Rays location on the electromagnetic spectrum. X-Rays are the type of radiaton between Ultraviolet and Gamma-Ray. X-Rays have a wavelength from .01 to 10 nanometers. The frequency of an X-Ray ranges from 30 petahertz to 30 exahertz.

Properties of X-Rays: 1. Travel in straight lines at the speed of light. 2. Can't be detected by human senses. 3. Penetration depends on their energy and the matter they are traveling through. 4. Energetic enough to ionize matter and can damage or destroy living cells. 5. Their paths can't be changed by electrical or magnetic fields. 6. Can be slightly diffracted at junctions between two different materials.

is for Yucca Mountain Yucca Mountain, a piece of federally owned land in Nevada, is the future location of the United States' first permanent nuclear waste repository. Once the plans have been approved and construction completed, 70,000 tons of radioactive waste from temporary storage facilities across the United States will be stored in Yucca Mountain .

........lIjii~ The

majority of the United States' nuclear waste is currently stored in temporary facilities. Many spent nuclear fuel assemblies are kept in large pools of water at the nuclear power plant, where they must be carefully monitored to prevent the waste from initiating any uncontrolled nuclear reactions. Fuel assemblies are often left in those pools for an indefinite amount of time. Nuclear waste is also stored above ground in heavy steel containers called "dry casks," which are not meant to survive more than a few decades.

The solution that Yucca Mountain is planning to implement is called "deep geologic disposal." The waste will be put into canisters that are specially designed to endure hazards such as earthquakes, volcanic eruptions, extreme temperatures, and corrosion for the next 10,000 years. After all of the waste has been put into storage, it will be supervised for the first hundred years of the site's operation, and then perma nently sea led off.

Nuclear waste will be stored in tunnels inside of Yucca Mountain.

It is impossible to attempt to foresee all of the forces that will be acting on Yucca Mountain thousands of years in the future. This makes it difficult to design containers that will be able to hold the waste in Yucca Mountain that will satisfy the security demands of the public. Some of the most prominent components of high level waste are unstable by-products offission power, such as strontium-gO. They are highly radioactive and long lived. Strontium-gO is a thousand times more radioactive than regular uranium, and takes about 10,000 years for it to decay to the same level of radioactivity as uranium that is already found in the earth. However, the containers for the waste do not have to be completely and totally secure for that long. The radioactivity of the waste will decrease exponentially over time. After 300 years, the strontium-gO will only be a hundred times more radioactive than ordinary uranium ore, as opposed to a thousand.

Proposed Waste Package Design

Five cylinders filled with high level waste are grouped together with one used fuel assembly.

They are placed into a SOmm inner canister made out of nuclear grade stainless steel, which is encased by a 20mm outer canister made out of a corrosion-resistant alloy. The outer canister is very difficult to fracture and can last for thousands of years.

These waste packages will be shielded from water and falling debris by a titanium drip shield, which overhangs the entire tunnel.

is for Absolute Zero

-459째 F

-273째 C

o Kelvin

Absolute Zero cannot be reached experimentally, although it can be closely approached.

Absolute Zero represents the coldest temperature that anything in our universe could ever reach. As far as we know, it is possible to heat objects up indefinitely - there is nothing to stop an object from getting hotter and hotter as we heat it more and more. When we think about temperature, we think about how hot or cold something is. What we are actually measuring when we read the temperature of a substance is the average kinetic energy that the molecules in that substance have. As we cool an object, the kinetic energy of each molecule decreases, and at absolute zero, there is no kinetic energy at all. Since kinetic energy is a measure of speed, at absolute zero all molecular motion stops. If we were to take an ideal gas and cool it, as we approached absolute zero the gas would have no pressure or volume. To get a feel of how cold absolute zero is think about walking outside in -459째 F weather!

=(1.8 x 0c) + 32

F Degrees Fahrenheit C = Degrees Celsius Kelvin

=째C + 273.2

As objects get colder, it becomes increasingly difficult to cool them further. There is always heat from something - the walls of a container, the cooling machinery, and the measuring equipment all allow a little bit of heat to sneak back into the system. This is why we can never completely remove an object from the rest of the universe. It is theoretically impossible to reach absolute zero. Scientists have come very close, however, and the coldest temperature that was ever reached here on Earth was one half of a billionth of a degree above absolute zero.

The diagram on top shows liquid hydrogen climbing up a surface as a superfluid. It is trying to equalize itself with the hydrogen inside of the "U" shaped object. The drawing below that shows a basic interpretation of viscosity. The green liquid represents high viscosity and the blue liquid represents low viscosity. It is simply showing the difference in thickness.

Atoms thot ore Heoted

88&&8Bff588 Atoms close to Absolute Zero

Above are two examples of temperature affecting the speed of atoms. The one to the left shows warm atoms and the one to the right shows atoms at the absolute zero state. Atoms at high temperatures move rapidly, while atoms at absolute zero don't move at all.