UNIT 6 ENERGY
CONTENTS
Fuentes de energía. Renovables y no renovables. Limpias y contaminantes. La luz como fuente de energía. Propagación, refracción y reflexión. El sonido como manifestación de energía. Características del sonido: timbre, tono e intensidad. Trasmisión del sonido.
ESTÁNDARES DE APRENDIZAJE 4.4.1 Diseña sencillas experiencias que determinen la necesidad de la energía lumínica como elemento imprescindible 4.4.2 Identifica algunas características del comportamiento de los cuerpos en función de la luz, la reflexión de la luz y la descomposición de la luz blanca. 4.4.3 Planifica y realiza experiencias diversas para estudiar las propiedades de materiales de uso común y su comportamiento ante la luz 4.5.1 Conoce las principales características del sonido. Observa e identifica el tono, intensidad y timbre. 4.5.2. Identifica las principales características de la transmisión del sonido en diferentes medios, ejemplificando algunos casos. 4.5.3 valora la importancia de la ausencia de ruido y de contaminación acústica y propone actuaciones para combatirlo 4.5.4 Planifica y realiza experiencias sencillas para estudiar efectos del sonido y su propagación. Comunica de forma oral y escrita el proceso y el resultado obtenido.
UNIT 6 ENERGY In themselves Performing Reservoirs Electric turbines Stored Allow Inner Come from Appliances Devices Convert Sources Resource Run out Fossils Pollute/polluting Dense
blurrred Useful mainly generate large refineries biofuel biomass geothermal hydropower energy transparent translucent opaque reflection refraction dispersión of light waves
C.E.I.P. SANTA ANA (Madridejos)
vibrate as fast as intensity loud quiet pitch duration
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1. - ENERGY Energy is the property of objects to produce different changes in themselves or other objects like: performing a mechanical work, emitting light, heating a material... Energy is the ability to do a work. Batteries have energy. They can make a toy car move The wind has energy. The wind can make a kite fly or a tree fall down.
2 - TYPES ENERGY
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There are many different forms of energy.
Thermal/heat energy is the energy matter has got depending on its temperature. The Sun produces a lots of hot, and the inner of the Earth also produces a lot of hot. . Light energy. The Sun also produces light energy. Plants need this energy to grow. Sound energy. Everything that makes a noise, a vibrating drum for instance, produce sound energy comes from burning coal, oil and natural gas. Chemical Energy , is the energy we get from the food we eat Kinetic Energy is the energy of matter in movement. For example when you ride a bike you use kinetic energy Electrical Energy is the energy used by electrical appliances and electronic devices, such as television and mobile phones. Nuclear Energy is found in some substances such as uranium and plutonium.
ELECTRICAL ENERGY
TYPES OF ENERGY
LIGHT ENERGY
KINETIC ENERGY THERMAL ENERGY
MECHANICAL ENERGY
CHEMICAL ENERGY
ENERGY FROM FUEL
INTERESTING FACT Energy can change from one type of energy into another. This happens in nature and in many of the machines we use. In an electric fan, electrical energy is transformed into the mechanical energy of the moving parts. In a toaster, electrical energy is trasnformed into thermal energy So it is easy to convert electrical energy into other forms of energy. 3.– RENEWABLE / NON-RENEWABLE ENERGIES: An energy source is everything which can be used to produce energy for light, heat, machines There are two groups of energy sources: Renewable and non-renewable. 3.1.– NON-RENEWABLE SOURCES OF ENERGY:
A non-renewable resource is a finite resource. They run out as we consume them. Most of them are fossil fuels (coal, petroleum, natural gas, uranium…). They are very polluting for the environment, but nowadays most of energy consumed by human is from fossil fuels. A.– Coal: was formed by decomposition of great dense forests. They were buried under the soil, and temperature and pressure change them into coal. We use coal to produce electricity in thermal power stations.
B.– Petroleum: was formed millions of years ago, when large quantities of dead organisms (zooplankton, algae…) were buried under intense heat and pressure. We get butane gas, petrol, diesel fuel… that we use mainly for transportation, make plastics… They are produced in refineries. C.– Natural gas: is formed by methane and other gases, and it’s found in the extraction of petroleum or coal. It’s used for heating, cooking in houses, and electricity generation. D.– Nuclear power: is the use of nuclear processes to generate useful heat and electricity. Nuclear fussion of some radioactive elements (uranium…) produces a lot of energy in nuclear power stations. 3 3.2.– RENEWABLE SOURCES OF ENERGY: There are never ending energy resources that don’t pollute the environment. The most common ones come from the Sun, the wind and the water. a.- Solar energy: Solar panels get energy from the Sun to produce electricity and thermal energy to heat water. b.– Wind energy: win turbines produce electrical energy from the wind. c.– Hydropower energy: stored water in reservoirs contains a large amount of energy. This water moves electric turbines to produce electricity. d.– There are other renewable resources of energy like: .– Biomass: obtaining energy from organic matter to produce biofuel. .– Geothermal: is a type of energy generated and stored in the Earth’s crust, used for heating and electricity. 3
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4.– LIGHT: Light is a kind of radiation (energy) from light sources that permits us to see objects and distinguish shapes, sizes and colours. There are two types of light sources: .– Natural sources: like stars or the Sun. They produce their energy from nuclear explosions on the Surface .– Artificial sources: like light bulbs, fluorescent tubes, candles… Light travels in straight lines and we see objects because they reflect light. In a dark room Natural and artificial we can’t see anything because objects don’t reflect light, 6 sources of energy
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4.2.– LIGHT AND MATTER: When light gets to an object, light can pass through it or can’t depending on the material of the object. Materials can be classified in three groups: A.- Transparent materials: they allow light to pass through the material, and we can see clear images behind them (water, glass windows…). B.- Translucent materials: they allow light to pass through the material, but you can’t see clear behind them, you only can see blurred objects (some kinds of plastic or glass). C.- Opaque materials: they don’t let any light to pass through the material, and you can’t see anything behind them. They produce a shadow (a dark space behind an opaque object with light in front of it (wood, metals…) 7
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Types of materials: .– Transparent. .– Translucent. .– Opaque.
Transparent
Translucent
Opaque
4.3.- PROPERTIES OF LIGHT.
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Light travels in straight lines Light has two main properties: reflection and refraction. A.- Reflection: is the change in direction of light when it collides with a body, and light returns (is reflected) and then we can see this body. Reflection permits us to see objects. A mirror is an opaque body with a polished surface that reflects light and images. B.-Refraction: an effect that occurs when light bends as it passes from one substance into another. Water, clear glass, lenses and air refract light.
C.- Colour: White light from the Sun is formed by seven colours from the rainbow: red, orange, yellow, green, blue, indigo and violet. Primary colours are red, green and blue. Dispersion of light is the separation of white light into the seven colours. When it rains, and sunrays go through drops of water, white light disperses and forms the rainbow in the sky. When objects receive white light, they absorb different colours and reflect the rest of them. If we see an object in red, is because the object absorbs all colours and it reflects red. Snow reflects all colours, so we can see it in white. On the contrary, coal absorbs all colours and doesn’t reflects any of them, so we see coal in black. 10
5.- THE SOUND.
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It is a form of energy that is produced when objects vibrate. Sound travels in waves, and travels in all directions . Sound can travel very fast but not as fast as light . Loud sounds travel further than quiet sounds, and a sound is always louder near its source. Sounds can be produced in many ways: from a hit, a scratch, a blow… These actions make objects vibrate, so they produce different sounds. Waves travel Sound waves from an exthrough the air and come to our ears, and finally our brain listens to the sound. plosion break windows. Sounds can travel through air and water and, it can travel through solid and opaque objects. But sound can’t travel when there’s no air. This means that there is no sound in the space or on the moon.
Sound travels under the water
Sound travels in all directions
Sound travels through solids
Sound can reflect off some object, like light. When this happens, we can hear an echo.
5.1.–CHARACTERISTICS OF SOUND.
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When an object vibrates, produces a special sound. This sound is transmitted by waves. These waves have a frequency.
Loud sound (high volume)
Human ear can identify different sounds because of their characteristics. 1.– Intensity (volume): is how much energy a sound can transfer. There are: Loud sounds (very intense: a scream). Quiet sounds (less intense: a whisper). 2.– Pitch: is the number of vibrations per second of the sound. There are: High pitched sounds (high frequency: lots of vibrations per second). Low pitched sounds (low frequency: few vibrations per second). Children have high voices and men have low voices. 3.– Quality or timbre: is the difference in the quality of sound. This is the reason because we can distinguish one source of sound from another one. We can identify one person from another one, or an instrument from another one. 4.– Duration: is the length of the sound from the moment that it starts, till the moment it finishes. There are short and long sounds.
Quiet sound (low volume)
High pitched (a whistle)
Low pitched (a bass guitar)
ACTIVITY 1: Look at the photograhps. Name the type of energy.
ACTIVITY 2: Circle and write the six types of energy named in the previous activity. N
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ACTIVITY 3: What energy transformations are taking place? Match the sentences to the photograph
A.– Electrical energy is transformed into heat energy B.– Mechanical energy is transformed into electrical energy C.– Chemical energy is transformed into light energy
ACTIVITY 4: Read the sentences and circle the correct words.
A. B. C. D.
Coal, petroleum and natural gas are renewable energy sources/fossil fuels. Petroleum is extracted from mines and deposits/oil fields. Natural gas and coal are used directly as fuels/ to produce fuels. The main use of natural gas and coal is to produce electricity/petrol.
ACTIVITY 5: Read the sentences and write renewable energy or non-renewable energy a. b. c. d.
These sources never run out, or they can be renewed………………………………… Examples are sunlight and wind………………………………………………………………………… These sources will eventually run out. They cannot be replaced……………………………………….. Examples are uranium and petroleum………………………………………………………………….
ACTIVITY 6: Copy the chart and classify the energy sources Oil
wind
gas
coal
RENEWABLE
the Sun
water
NON-RENEWABLE
ACTIVITY 7: True or false? Copy the sentences and correct the ones that are false a. Light always travels in a straight line b. Light travels in all directions c. Light is the slowest form of energy
ACTIVITY 8 : Answer
the following questions about light.
Where does light come from? How does light travel? How do we see? Why do leaves look green? How do mirrors work? Why do my legs look crooked underwater?
ACTIVITY 9: EXPERIMENT WITH LIGHT Classify the following objects into translucent, transparent and opaque A piece of Wood paper Tinfoil
a plastic bag a cardboard glass sunglasses tissue paperbag plastic bag blue plastic bubble wrap
TRANSLUCENT
TRANSPARENT
OPAQUE
ACTIVITY 10: Why do objects look red under red light? Materials piece of red plastic to act as a filter light source (light bulb or torch) White object Instructions 1. Place a white object on the desk. 2. Switch on your light source and place the red plastic in front of the light. 3. Shine the light (with the red plastic in front) onto the piece of white paper. Questions What color was the page under normal light? …………………………………………………………………………………………………………………………………………………………. Why does the page appear white under normal light? …………………………………………………………………………………………………………………………………………………………. What do you see when the red plastic filter shines on the white paper? …………………………………………………………………………………………………………………………………………………………... Explain why the paper change the color.
PROYECT 1: Identify the objects by listening the quality (timbre) of the
1 1 2 3 4 5 6 7 8 9 1 0 3 1 2 3 4 5 6 7 8 9 1 0
TRANSPORTATION SOUNDS Bike
HUMAN BODY SOUNDS Laugh
2 1 2 3 4 5 6 7 8 9 1 0 4 1 2 3 4 5 6 7 8 9 1 0
ANIMALS Dog
HOME STUFF SOUNDS Door
LITTLE PROYECT 2: HOW I USE ENERGY 1.– Write a text about the forms of energy you use. a. b. c. d. e.
What forms of energy do you use every day? How do you use these forms of energy? Identify the sources of some of these forms of energy. Are these energy sources renewable or noon-renewable? How do you save energy?
2.– Find photos or draw pictures to illustrate your text.