OYLA Youth Science, May 2017, preview

Popular-Science Magazine for Students and Their Parents

#2 2017 MAY

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WHO WAS Đ?E? HE?

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774006 772537 9

774006 772537 9

ISSN 2537-7744

ISSN 2537-7744

NZD

What happened to humans’ long-lost relatives? p. 4 How do scientists know the age of our planet?

p. 10

Table of contents Put down that fly swatter!

These insects save lives. p. 22 Have you ever wondered

why you have toes? p. 30

Test your erudition

Is each snowflake truly unique? p. 16

Have you ever wanted an identical twin? p. 24

Discover the secrets hidden in this famous smile

p. 52

p. 29

Stonehenge: the monument that has baffled humans for centuries Delving into the ancient history of algebra p. 86 How do you make a сloak of invisibility? p. 75

Learn about the latest in 3D printing technology p. 56

Learn the secrets to business

success p. 40

Self-propelled

Harvesters

p. 48

How math helps geography

p. 92

p. 76

Netherlandish proverbs – a creative depiction of Dutch words of wisdom p. 54

Rocket’s FAQ

How to bring down the house p. 62

p. 36

The largest dam in the world

p. 46

A N T HROP OLOG Y

HUMAN COUSINS A huge head, nose, arms, legs, and chest, remarkable strength… and striking blue eyes. Before us stands a member of parallel humanity. Meet Neanderthal.

The Tree of Humanity A hairy, humpbacked ape reluctantly trails behind a still hunched, but less hairy ape.

The less hairy ape shuffles behind a completely hairless, but still round-shouldered ape. And beyond the round-shouldered ape strides a human: Homo sapiens. Do you remember seeing this picture in your biology textbook? Well, forget it. That’s not how it happened.

But let’s not get ahead of ourselves. We, humans, are called Homo sapiens. The word Homo refers to our genus (“human”), and sapiens is our species (from Latin, meaning “wise”). So, Homo sapiens means “a wise man.”

A tree. Bushy. Broad. Dense. This is what our genus, Homo, looks like. There are no

straight branches, where one ape transforms into another, and then another.

The biology textbook’s rendition of the development of Homo sapiens shows a neat, straight line for illustration purposes only. In reality, everything was far more complex.

Before the “pinnacle of God’s creation,” Homo sapiens, saw the light, some other variations of us existed on Earth: they were members of the genus “Homo,” but they belonged to other species (that is, not to “sapiens”). The most well-known among them were the Neanderthals, our relatives.

But they are not our direct ancestors (not our “moms” or “dads”), but rather more like our “cousins” or “uncles.”

These Guys Are Tough The first Neanderthal skeletons were found in 1856 in the Neander Valley in western Germany — hence the name Neanderthal, or Palaeoanthropus, as they are also known.

They lived long ago, as far back as 28,000 years ago. They were like real-life Mariusz Pudzianowskis of the Stone Age (Mariusz Pudzianowski is the five-time winner of the title “World’s Strongest Man”). Even Neanderthal women had broader shoulders than the majority of men today, through their height was short, at around 150–160 cm.

The Neanderthal had a receding forehead, a huge, protruding nose, sloping cheekbones, massive wrists, a barrel chest and a large, flattened skull. They had no chin, but did have a strange bulge on the

back of their head, like a chignon used by women to fasten their hair. In addition, most of them had red hair and blue eyes.

These freckled redheads mainly lived in caves in the territory of modern-day Europe, but there were also some who settled in Altai and the Middle East.

Chemists and doctors We use the word Neanderthal as an insult, usually to describe stupid people. But we are mistaken. In the past, scientists really thought that the Palaeoanthropus were dim-witted. As they say, brawn over brains.

But modern anthropologists (scientists who study the structure of human ancestry) are

more and more convinced that Neanderthals were no dimmer than our direct ancestors, the Cro-Magnon people (a name for early Homo sapiens).

The Neanderthal’s brain was even bigger than ours. But it had a different shape: the back was well-developed, but the front was flat. They could probably even speak. What they lacked was … imagination. But that doesn’t mean that they were stupid.

Meanwhile, Cro-Magnons at that time were already whittling statuettes from mammoth tusks and elephant ivory (the famous Paleolithic Venus figurines), carving bone flutes, sewing clothes and making jewelry. Sapiens were creative. Neanderthals, however, fell short. They could make

PHYSICS

Meteorite as a clock With the human skeleton, everything is easy — he lived not so long ago, in principle, even without complex calculations we can understand when exactly. But what about the planet Earth? During its appearance there were no living organisms, there were only stones and minerals. Therefore, to calculate the age of the Earth, we need to determine two things: what isotope we will use for clock reconciliation and what stone to choose for estimating the content of the radioactive isotope.

To begin with, we will need a radioactive isotope with a sufficiently long half-life. Uranium meets these criteria. The final and stable product of the decay of uranium is lead (Pb). The half-life of uranium to lead depending on the uranium isotope (U238 or U235) is either 4.47 billion years or 740 million years. The method of estimating the age of rocks is called uranium-lead.

Then we need a rock the age of which coincides with the age of the Earth. The truth is there is one problem — most rocks on Earth are not able to indicate the exact date of birth since most of them represent a mixture of rocks of different ages. And what if we take a rock that flew in the form of a meteorite from the cosmos?

This was done in 1953 by Claire Patterson, a man who for the first time calculated the correct age of the Earth. He believed that meteorites are residual material from the time of the formation of the solar system and, thus, having calculated the age of such a meteorite one can measure the age of the Earth. As a sample, Claire took a Canyon-Diablo meteorite that fell to Earth about 50,000 years ago. The Earth’s age published

by Claire Paterson was 4.55 billion years (plus or minus 70 million years). Until now, this estimate has not changed much. In fact, we used a method similar to the method we used to calculate the age of the human skeleton.

Fragment from the Cañon Diablo meteorite

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UNLIMITED POSSIBILITIES There are dozens more examples of the use of isotopes, such as the sterilization of tools, fighting cancer, and studying the mechanism of organic reactions with labeled atoms.

Isotopes in medicine Both radioactive and stable isotopes are widely used in medicine to diagnose and treat illnesses. There are many applications for isotopes in biomedical research and other areas such as chemistry, physics, and biology.

There are many radioisotopes which are used to treat some diseases. Cobalt-60 (Co-60) is used to damage kill tumor tissue in a process known as radiotherapy. Gamma rays are also used to sterilize medical instruments, including surgical equipment and bandages.

Isotopes in agriculture Like medical industries, radioisotopes and stable isotopes are also used in agriculture. They are used to create mutations in insects to kill them or make them sterile. This method helps in pest control.

The radiation emitted by radioisotopes can be detected using a Geiger-Müller counter. C-14 is mainly used to study carbon in plants during photosynthesis.

Isotopes in daily life Isotopes are also used in our daily life. Na-24, for example, is used to detect when underground pipes are leaking. Beta rays help control the thickness of plastic, paper and metal sheets.

Na-24 is also used to measure how quickly the engine in a vehicle wears out. Co-60 helps in food preservation. It kills bacteria in food, making fresh produce last longer without affecting the quality or flavor.

What did the two scientists say when they saw two helium isotopes?

HеHе!

But the important thing is that we hope that you, our dear readers, have understood the essence of the matter. This is only one principle, but look at how much scientists were able to extract from it, and how many interesting and useful things they came up with! How many more new opportunities will science uncover? One can only imagine!

PH Y SIC S

HIEROGLYPHS

from the sky O

n January 28, 1887, in spite of the relatively warm weather, the shore of the Yellowstone River was blanketed by an astonishing snowfall.

A body of cavalry watching over the Sioux Indians became witnesses of this unique natural phenomenon. Amidst the falling snowflakes, one attracted attention above all the rest: it was nearly 40 cm in diameter.

Even today, this is recorded as the largest snowflake ever seen.

Such large flakes appear during warm winter weather. It is much colder up in the

What are snowflakes?

Is it true that no two are alike?

atmosphere where snowflakes are formed.

As they fall, they melt a little and stick together. If you catch one on your mitten, you can see that it actually consists of several different flakes. And each one is unique.

But how do we know that? Has someone examined every snowflake in the world and said for certain that none of them are alike?

Of course not! But that doesn’t stop scientists from saying with confidence that there could never be two identical snowflakes. To understand why, we have to figure out what snowflakes are and how they appear.

Six Points When liquid water or steam freezes, it forms ice crystals. Remember: steam is a gas, and its water molecules float almost freely. Ordinary water is a liquid, whose molecules are loosely bound to each other, flowing while only lightly clinging together.

And ice is hard: its molecules barely move, sitting in their places as if bound to the nodes of an invisible grid.

Different crystals have different grids.

Look at a grain of sugar: it is like a tiny cube, because the sugar molecules are

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Scanning electron microscope images of snow crystals

BIOLOG Y

“Extra” organs

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‘Granny, why do you have such big ears, such big eyes, and such big teeth?’ Little Red Riding Hood was eaten because she asked the wrong questions. But if she had asked why Granny needed her appendix, wisdom teeth and coccyx bone, the Wolf, surely, would have been so confused that the girl could have run away in time. But really, why do we need these organs?

Vestiges Or vestigial organs. This is what we call the parts of the human body that are no longer used as originally intended. And they can’t be used. What does that mean? Let’s figure it out.

Humans evolved from monkeys. You’ve probably heard this phrase. But it’s not true.

Man is a monkey — or rather, a primate (a term for a group of mammals including monkeys and humans). But we are not the same primates that you could see at the zoo (such as monkeys or chimpanzees), we are primates whose ancestors went extinct a long time ago. These ancestors are called Australopithecus.

In fact, that’s exactly why modern monkeys don’t evolve into humans — because they have already evolved. Some have evolved into gorillas, some into capuchin monkeys (a small monkey living in Brazil), some in macaques. And our ancestors evolved into us. And that’s it. The monkeys that are alive today are not our “ancestors” or “great-grandparents,” but only our “cousins” — the closest relatives to us among all the animals. That’s why they can’t turn into humans.

What does that have to do with vestigial organs? Nothing yet. Let’s keep going. It’s time to dive deeper into the darkness of the far distant past, when our progenitors were…fish. Just imagine. All the animals that live on land today (including humans), once came out of the water (after all, that was where life first appeared). But this happened a long time ago — millions of years ago. And while we may be a little bit similar to monkeys, we are nothing like fish.

But wait. We are not talking about the carp and pike that fishermen catch today, but about something in between fish and animals. This intermediate (transitional) form was called Tiktaalik. Scientists believe that this was the first creature to get out of the ocean and onto land. There is still very little resemblance. At least today. But all of us, before emerging into this world, “lived” in the womb of our mother. And at that time we really looked like a little fish. We even had… a tail. The rest of this tail is nothing more than our coccyx — the lowest part of the spine, which consists of three to five fused vertebrae, and helps us to keep our body in an upright position.

M AT H

Throughout the centuries, mathematics has helped people solve pressing issues such as dividing up an inheritance or sowing crops.

Today we will tell you about how the first equations appeared and why they were necessary. Don’t worry if you can’t remember the algebra or geometry you learned in school. There will be no tests, problems or complex formulas. On the contrary, we will try to look at another, more interesting side of mathematics.

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x

Finding

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M AT H

Mathematics as a Tool

of Geography

“In any particular theory there is only as much real science as there is mathematics.”

–Immanuel Kant

S

ince its inception, the history of mankind has been a history of voyages and geographical discoveries. In the old days, people usually traveled out of necessity, because they were looking for a favorable place to live with a mild climate, clean water, and an abundance of flora and fauna. People

have conquered rivers and seas, deserts and forests, oceans and continents — all in all, they have covered the entire Earth.

Those trips, of course, would have all been impossible without using maps. Archaeological findings confirm that mankind learned to create maps before even inventing writing.

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The oldest map Ancient maps depicted mountains, rivers, sea and forests. But on those maps you would not find information about the height, depth or breadth of these geographical objects or the features of the terrain. Primitive humans did not have enough technical skills and knowledge to measure or calculate these parameters. But the first step had been taken: people learned to depict the surrounding three-dimensional world on a twodimensional map. In the language of mathematics this is called a 3D projection onto a plane.

This primitive map of Abauntz Cave is a prototype of modern maps. A stone with drawings was found in 1993 in the cave of Abauntz in northern Spain.

Experts from the University of Zaragoza spent 15 years trying to decipher it and figure out its purpose. “We can say with certainty that it is a sketch, a map of the surrounding area,”— said Pilar Utrilla, the head of the research group.

Experts believe that the map was made about 14,000 years ago, and at the moment it is the oldest of all known maps. Nothing like this has been found on the territory of Western Europe up till now.

“Whoever made it sought to capture in stone the flow of the watercourses, the mountains outside the cave and the animals found in the area,”— one of the scientists said. — “The landscape depicted corresponds exactly to the surrounding geography. Complete with herds of ibex marked on one of the mountains visible from the cave itself.”

INTERPRETATION OF DRAWINGS ON T WO SIDES OF THE STONE оutline of the mountain

marks

river

ford

trail

pond

trail mark about an interesting place

ford

deer

river