Popular Science Magazine for Students and Their Parents
#52017
AUGUST
oyla-science.com
E AT DC OV ER
Friedrich Nietzsche
IM
LIFE WOULD BE A MISTAKE.
AN
WITHOUT MUSIC,
ANATOMY
TECHNOLOGY
How do night vision devices work? p. 38
What happens inside you when you hear music? p. 4
Digital Music: how do we use technology to capture music? p. 32
The story of one of the most
contentious Nobel laureates. p. 26
HISTORY
An Incomplete but Definitive
History of Music: tracing music through the ages. p. 16
ANTHROPOLOGY
The Stone-Age Orchestra: where did music first come from, and what did the world’s first concerts sound like? p. 10
CHEMISTRY
Why do we need machines the size of
an atom? p. 46
Carbon, Carbon Everywhere: why did nature choose carbon as the basis of life? p. 52
Table of contents MATH
Some mathematical constants are so famous they have their own holidays. p. 60
Nature’s Daredevils:
Why are mathematicians obsessed with prime numbers? p. 66
BIOLOGY
Superconductivity:
BIOLOGY
serious science made simple. p. 72
PHYSICS
Radiation? Acid? Ultra-high and low temperatures? These creatures can survive everywhere. p. 80
Extinct Giants:
p. 86
once upon a time, enormous snakes, sharks, dragonflies, and more roamed the earth. Get to know some of these great ancient beings.
Music in your head A N ATOM Y
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M
any animals are endowed with musical abilities. Seals, for instance, rhythmically flap their fins, whales are known for their songs, trained bears can dance, and everyone is familiar with the twitter of birds. But only a human can use music and melodies to express deep emotion. The father of evolutionary theory, Charles Darwin, described our special ability to perceive music as “the most mysterious with which [humankind] is endowed.” So, what is happening inside of us when we hear music?
Why shouldn’t you listen to very loud music? Loud sounds and constant noise damage the sensitive hair cells inside the ear, so they cease to distinguish sounds. The most vulnerable are those that react to high-frequency sounds — for example, whistling — which are important for understanding speech. Damage to these hairs accelerates with age, which is why elderly folk often have to ask people to repeat themselves. But among those who work in noisy conditions, or listen to loud music with earbuds or in-ear monitors, there are many people whose hearing has deteriorated much earlier. In a noisy place? Use earplugs. Like listening to music, audiobooks, and podcasts? Choose over-ear headphones, whose source of sound is located outside the ear canal. Take care of your ears starting while you are young.
From Wave to Ear Sound is the mechanical vibration of molecules of a substance (for example, air). Everything we hear — speech, songs, street noise — is a set of sound waves, similar to ripples on water. The volume of sound depends on the height of the wave, and the distance between the waves determines the tone’s frequency: the smaller the distance, the higher the sound. Variations in these characteristics create a range of sounds all around us. The sound wave is caught by the outer ear — the auricle and the ear canal. Then, movement of the small bones of the middle ear transmits the vibrations to the inner ear, called the cochlea. One of the bones of the middle ear — the stirrup — knocks on the fluid-filled cochlea, changing the pressure inside it. This causes a shift in the liquid, moving the inner hair-like cells of the cochlea. Each cell is tuned to its own frequency of sound wave vibrations and has a bundle of hairs on its surface. The hairs, oscillating in time with the wave, convert the sound vibrations into an electrical signal — a kind of “language” which neurons can understand. And so the “recoded” information, also known as a nerve impulse, is transmitted simultaneously from both ears to the temporal lobes of the brain, using the neurons of the auditory nerve.
Brain
Cochlea nerve
Brain stem
Cerebellum
Auditory nerve (hearing nerve)
Ear flap (auricle)
Hair cells Semi-circular canals Cochlea External ear canal
Middle ear Tympanic membrane (ear drum)
Malleus, Incus and Stapes
Eustachian tube
A N AT O M Y
From Ear to Brain But music is not merely sounds — it is a complex arrangement of them. As a result, there is not just one part of the brain responsible for perceiving music, but several connected working zones which are each involved in processing various components of music. The auditory cortex in the temporal lobe of the brain evaluates the sound’s pitch and the rhythm and harmony of the music. Our brain must first ensure that the source of the new sound is not dangerous. The signal enters the cerebellum, which is responsible for spatial orientation and movement coordination. What if we are faced with something dangerous and need to prepare for fight or flight? The hippocampus, the brain’s memory center, evaluates the danger, which compares the new situation against its “archive.” Has anything like this happened in the past? If it has happened before and everything ended up fine, the hippocampus cancels the alarm and “updates the archive.” New connections are created between neurons as the brain remembers this new information. Next time, we will immediately recognize that melody, even if we are in a very noisy room. Additionally, thanks to the hippocampus, events from our life and the music that we listened to at these moments are firmly connected. The music that we listen to up to 20 years of age is especially memorable, as this is the period of the active development of our brain. Our tastes may change with time, but the songs of our youth will leave a particularly strong imprint if they are associated with strong emotions, dreams and difficulties in our life.
CORPUS CALLOSUM Connects both sides of the brain
A LZ H E I M E R’S is a serious disease of the central nervous system. One of its symptoms is memory loss. Patients may forget most of their personal information, such as birthdays or names of family members, but they can remember songs they heard in their childhood or adolescence. With the help of music therapy, patients are stimulated to recall memories of past events associated with specific melodies.
HOW DO WE KNOW THIS? During the execution of certain tasks, the areas in the brain responsible for these operations are activated. This process can be visualized with the help of MRI — magnetic resonance imaging. The activity of a region resembles the flare of a firework. With the help of this method, scientists have established that when responding to music, both brain hemispheres are activated, with the left perceiving the rhythm and the right perceiving the melody and tone. Actually, before the discovery of MRI and other methods of visualizing the activity of the nervous system, scientists still studied the brain’s musicality, by observing the victims of diseases and accidents which caused them to lose certain musical skills.
SENSORY CORTEX Controls tactile feedback while playing an instrument or dancing AUDITORY CORTEX Listens to sounds; perceives and analyzes tones
MOTOR CORTEX Involved in movement while dancing or playing an instrument
HIPPOCAMPUS Involved in music memories, experience and context
PREFRONTAL CORTEX Controls behavior, expression and decision making
NUCLEUS ACCUMBENS & AMYGDALA Involved with emotional reactions to music
CEREBELLUM Involved in movement while dancing or playing an instrument, as well as emotional reactions
VISUAL CORTEX Involved in reading music or looking at your own dance moves
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THE BRAIN IS CONSTANTLY CHANGING
CAN EMBRYOS HEAR MUSIC?
For example, perhaps as a child you learned to play a musical instrument, then quit music lessons and many years later discovered that you had forgotten how to play the instrument. This is not surprising: connections between neurons that have not been used for a long time disappear. But for those who systematically practice music, amazing changes occur in the brain. The corpus callosum develops, the brain region responsible for the connection between the cerebral hemispheres. Thanks to this development, signals move between the hemispheres much faster and along more sophisticated routes, so consistent music lessons contribute to excellent development of thinking and memory.
The human embryo begins to hear music from the fourth month of intrauterine development. This is the time when hearing organs begin to form. By the sixth month the cochlea is formed. The embryo hears sounds through the amniotic fluid. Imagine diving underwater and trying to hear what is happening on the surface. The sounds of the outside world are audible, but muffled. It is nearly impossible to tease apart the individual threads of a melody. And yet, even in the first months of life, newborns can distinguish dissonance in rhythm. The brain’s reaction in this case is very similar to the reaction of an adult brain to an incorrectly constructed phrase.
THIS IS YOUR BRAIN ON PIANO Playing the piano is fun. But check out all the things your brain is doing at once!
EYES
EARS
Sight-reading on the piano involves two lines of music, each on a different clef.
Pianists listen to notes being played and adjust their playing accordingly.
VISUAL CORTEX
TEMPORAL LOBE
OCCIPITAL LOBE
KEEPING TIME
TWO HANDS Both hands often play intricate rhythms independently from each other. PRIMARY MOTOR CORTEX PREFRONTAL CORTEX
AUDITORY CORTEX
CEREBELLUM
Pianists accurately “keep time” by synthesizing and synchronizing all sensory input and motor activity. In addition, they are able to subdivide the beat in a myriad ways. PREFRONTAL CORTEX
CEREBELLUM
10 FINGERS
SPATIAL
Very few, if any, instruments require the use of all ten fingers.
Pianists know where all the notes are without having to look at the piano keyboard.
PRIMARY MOTOR CORTEX PREFRONTAL CORTEX
PARIENTAL LOBE CEREBELLUM
RIGHT HEMISPHERE
CEREBELLUM
A N T HROP OLOG Y
THE STONE-AGE ORCHESTRA
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Once upon a time, our greatgreat-great…great-grandfather feasted on the wings of a giant griffin vulture (a type of mountain bird). And then he accidentally blew into the hollow, narrow bone of the animal. A whistling sound emerged. That, or something like that, is how the first musical instrument in the world—the flute—appeared. And then it carried on from there.
How did music first appear? When you’re listening to your favorite song, it makes you happy. But why? It’s hard to say. Also, how can we understand how and why music appeared at all? The great English naturalist and author of the theory of evolution, Charles Darwin, wrote: “As neither the enjoyment nor the capacity of producing musical notes are faculties of the least direct use to man in reference to his ordinary habits of life, they must be ranked among the most mysterious with which he is endowed.” Darwin posited that music could serve as a means of attracting the opposite sex. Like the tail of a peacock. Like a band’s performance that causes screaming fans to lose their minds… Regardless of whether music was created accidentally or for some evolutionary purpose, it is certainly fascinating, and attractive to the opposite sex. But what is the source of music? The first thing that comes to mind is the singing of birds or whales. But can we call these noises singing? Most researchers don’t consider it so—it’s more likely a form of communication, similar to human language, but far simpler. Depending on the duration and timbre of this or that sound, animals can transmit different
HOW I T WORK S
THROUGH
A GLASS, DARKLY
Since the time when humans tamed fire, we have not been afraid of the night’s darkness. Light can help us to orient ourselves on land, in the air, or in water, but it simultaneously reveals its owner. If you see, you can also be seen. From the beginning of the twentieth century, scientific thought has solved this problem with the invention of night vision devices.
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Photocathode is a fancy word for a device for capturing weak
IR radiation. As soon as a quantum of light enters the device, the photocathode emits an electron. What for? The electrons are intended for the phosphor on the bottom of the small inner glass, which glows upon being hit by these electrons. And the phosphor glows, naturally, in the visible light range. So magically, the invisible becomes visible. During World War II, Holst’s glass became a very important basis for the Sperber night vision equipment, which was used in the aforementioned Panther tanks. In Germany, assault rifles were mounted with bulky 35-kilogram night vision devices called “Vampir.” During the attack on Okinawa, Americans adapted this M1 infrared night sighting device, calling their version the “sniperscope” or “snooperscope” and mounted onto helmets. This gave them a decisive advantage over the unlucky Japanese. The Red Army of the Soviet Union also did not do without night vision: they had the “Omega VEI” underwater infrared detector, the “Gamma VEI” binoculars, and tank-driving devices with the amusing name “Dudka,” a type of flute. All of these developments were quite small and applied in a limited, albeit highly effective, manner.
Diagram of the Holst Glass The invisible image of an object
Holst and His Glass First of all, night vision allows for covert military operations to be conducted under the cover of night. It is unsurprising that the first night vision apparatuses appeared on military equipment. So, in March of 1945, the practically destroyed Fascist Third Reich was one of the first in the world to introduce Panther tanks, equipped with these types of devices, into battle. It happened in Hungary on Lake Balaton. The introduction of this new device proved successful — in one night, the machines were able to penetrate 60 km deep past Soviet lines. German designers had already applied the classic principle of “victory over the night” based on the transformation of invisible infrared (IR) radiation (wavelengths from 1 mm to 780 nm) which is reflected from the observed object into visible light (wavelengths from 780 to 380 nm). The core of this ability was the Holst glass, developed in Holland in 1934. This isn’t a glass that you drink from, but an optoelectronic converter of infrared radiation.
A group of engineers, led by Gilles Holst, developed a design of two nested cups with flat bottoms, which are covered with photocathode and phosphor.
–
4 kV
High-voltage current source +
Electron stream e e e
Phosphor screen
e
e
Objective lens Photocathode
e e
Eyepiece e
Glass cup
A German “Panther” tank with a “Sperber” night vision device
Visible image of an object
M EG A PI XEL
60x
magnification
YO U S E F A L H A B S H I
Oak Timberworm The Oak Timberworm (Arrhenodes minutus) is the one of the pests of wood in North America (the male beetle depicted). The females of these beetles lays fertilized eggs on the back of oak trees in injured areas then pushes the eggs inside and covers them with feces and wood shavings. If no injured areas are available, she uses her long beak to break into the bark to create an opening. The male will guard her while she works.
The newly hatched larva begins to born into the wood, eating it as they go. The larva’s tunneling through the wood damages the usability of the oak once it’s harvested, leaving what look like pin holes in the timber. These markings are numerous and unsightly, making the wood a poor choice for ooring, furniture and other products, which lowers its grade and value.
4x magnification
BIOLOG Y
Nature’s
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Daredevils Compared with these animals, we are all total sissies. They are capable of living in high radiation, boiling water, the Dead Sea, and even outer space. They have earned their name: extremophiles. That is, those who love extreme living conditions.
Almost all of them are extremely small, and many can only be seen through a microscope. Let’s take a peek down the ocular.
Space Bears That’s what researchers nicknamed this surprising creature with eight short, thick legs with claws at the ends, and a chubby, segmented body. This is not a giant shaggy beast, but rather, a microscopic invertebrate—measuring from 0,1 to 1,5 millimeters in length. They don’t eat raspberries or honey, but feast on moss and algae. Meet the tardigrade (from the Italian tardigrada or “slow stepper”). And it definitely doesn’t hurry when walking—it moves at a pace of 2–3 mm per minute. In general, it’s a small and slow micro-animal. But appearances can be deceiving: tardigrades are some of the most tenacious creatures on our planet. If not the most. They can beautifully endure oxygen starvation on Himalayan peaks (up to 6 thousand meters above sea level), strong pressure in the depths of the ocean (tardigrades have been found up to 4,000 meters below sea level), fierce cold (they are found under arctic ice shelves), and extreme heat (they even live in the vents of volcanoes). But most importantly—tardigrades have endured outer space, without air, without water, where it terribly cold, and there is strong radiation. Swedish scientists learned of this when they sent these tiny beings into Earth’s orbit. After ten days on board, the researchers discovered the tardigrades had dried out. After they were returned to the space station, the tardigrades… came back to life. But that’s not all! There was a famous case where moss, which had dried up about 120 years ago, was rehydrated. And then a near-miracle happened: to everyone’s shock, after some time, a small herd of these creatures was quietly stirring in the moss. That means that tardigrades can be dried out entirely like leaves in a herbarium, and then come back to life. It is true that they all died quickly after that. But the fact remains that tardigrades can be practically resurrected from the dead!
BIOLOGY
Archelon When translated from Greek, this animal’s name means “ruler turtle.” This sea turtle, which lived between 145 and 66 million years ago, was the size of a small room (in length and width, but not in height, of course). The largest examples reached 4.6 meters in length and had a flipper span of about 5 meters. The archelon, considered to be the largest turtle to ever exist on Earth, weighed more than 2,200 kilograms. This turtle also had a large, curved beak, similar to that of an eagle. Its shell was not made of bone plates, like modern turtles, but rather of very thick and tough skin. Therefore, archelon is clearly related to the leatherback turtle. The latter have survived to this day. They are represented by a single species, which also happens to be the largest living turtle. The animals is called the leatherback turtle or the luth (which reaches about 2.6 meters in length and weighs almost a ton). The archelon, like modern leatherback turtles, probably fed on jellyfish and crustaceans. Archelons could also fall into a kind of dormancy, burrowing into the mud on the seafloor, and floating up to the surface only once every few hours to swallow up some fresh air. They also laid eggs on dry land.