1. Chameleons change colour in order to hide
False. A chameleon's skin can change colour from green to black, red, blue, purple, or multicoloured, but the amazing trick is not meant to help the animal hide – on the contrary.
Just like numerous other lizards, chameleons are well hidden in their natural surroundings, as long as they keep their green colour. When they change colour, they often become extremely visible, and that is the idea.
The beautiful colours are primarily used for unambigous communication with peers. Brightly red males can make their rivals flee, and pregnant females can tell horny males that they are wasting their time.
The colour change often takes place, as the animal gets excited, such as at the sight of another male. Hormones and signals from the brain make microscopic crystals in the skin cells change structure to reflect the light differently and so appear in a different colour.
In other cases, chameleons use the colour change to control their body temperature. When the animals are cold, they make their skin darker to absorb more heat from the sunlight.
2. Mount Everest is the world’s highest peak
False. The peak of Mount Everest rises high above sea level, but when it comes to the distance from "head to toe", the mountain loses out.
Mount Everest rises 8,848 m above sea level, higher than any other mountain, but the peak’s distance from the ocean surface is not necessarily a good measure of the mountain’s height. Mount Everest is located on a plateau and actually only measures 5,400 m from "head to toe". In this respect, Everest is dwarfed by the extinct Mauna Kea volcano in Hawaii, which only rises 4,207 m above sea level, but its "toe" is located deep below the ocean surface. It measures no less than 10 km from "head to toe".
Neither does Everest’s title as the world’s highest mountain mean that it rises the highest above the centre of the Earth. That title is held by Mount Chimborazo in Ecuador, whose peak is located more than 2 km higher above the centre of Earth than Mount Everest’s is.
3. Sugar makes kids hyperactive
False. Most parents would agree that kids become hyperactive after consuming too much candy or red cordial. However, scientific experiments tell a different story.
An extensive American study did not demonstrate any difference concerning the effect of sugar and artificial sweetener on children's behaviour. In another study, scientists gave all the kids an artificial sweetener, but told half of the parents that their kid had consumed sugar. In this group, the parents behaved differently to their kid, subsequently reporting hyperactivity. So, the myth is false, but so die-hard that people see a connection, although it does not exist.
4. Diamond is the hardest material
False. Diamonds are much harder than steel and granite, but they are not nature’s most robust material.
Diamond has long been known to be the world’s hardest material, but the sparkling mineral is now only No. 4 or perhaps ranks even lower. In 2005, German scientists produced a much harder material consisting of densely packed, tiny carbon rods. Four years later, Chinese scientists studied two natural minerals, wurtzite boron nitride and lonsdaleite and calculated that they were 1.18 and 1.58 times harder than diamond, respectively.
Lonsdaleite primarily exists in meteor craters, as extreme pressure is required to produce the mineral; a pressure that can only occur by Earth’s surface in case of a meteor strike.
The difference between diamond and lonsdaleite is solely in the shape of the crystals' 3D grid. Both materials consist of carbon, and all atoms have powerful bindings to their cloesest neighbours in the grid.
5. Earth's gravitational field does not affect astronauts
False. ISS space station astronauts feel weightless, because they are constantly falling down.
It looks as if they are “flying”, but the inhabitants of the International Space Station (ISS) experience 90 % of the gravity that makes other people stand firmly on the ground – i.e. they are falling towards Earth. However, they never reach Earth, because they (and the space station) are moving forwards at a speed of 28,000 km/h, as they fall. So, they and anything else in an orbit will keep on falling past Earth.
Astronauts fly faster than they can fall
a. Earth's gravitational field is constantly attracting the space station and anything else.
b. The space station and its contents are also moving forwards at a high speed.
c. The combined effect of the two forces is a circular fall, wich will never strike Earth.
6. More births make population grow
False. The world population is quickly growing, but the increase is not due to the fact that women give birth to more children nor that the total number of births is growing.
In 1965, the average woman gave birth to 5.0 kids, and in 1985, it was 3.5 kids. Now, the rate is only 2.4. That is only slightly more than the reproduction rate of 2.3, which is necessary to make a generation of children grow up to become just as numerous as their parents'generation. So although the number of women has risen dramatically since the 1980s, the annual number of births in the world has been fairly stable.
The explanation of the huge population growth of the past 100 years’ is that life expectancy increased more rapidly than the birth rate fell. Thanks to improved living conditions, fewer people die than those who are born. When, at some point in the future, the birth rate reaches the same level as the death rate, the population growth will cease, and the population will plateau.
7. Goldfish have poor memories
False. A goldfish brain might be small, but it demonstrates effective memory. Goldfish have a reputation for being unusually forgetful, but that is utterly wrong. The small fish can easily remember even complex problems after more than five months, according to experiments, in which the fish were trained to find their way through a maze.
At first, the fish spent several minutes passing through the maze, but they learned to make it in about 30 seconds. After the practice, they were moved to an ordinary aquarium and did not see the maze for almost six months. When they were placed in the maze again, they spent less than 30 seconds completing it. The result shows that the fish clearly remembered how to find their way.
8. Friction makes meteors burn up
False. Most meteors are converted into dust on their way down Earth’s atmosphere, but it is not the air particles’ friction against the meteors that heat the rocks and make them fall apart.
The heat is generated in the air in front of the meteor, where the air molecules are extremely compressed, and the high pressure makes the temperature rise, so the air catches fire. The heat affects the meteor’s surface and starts to consume the rock, until it is finally gone.
9. Women synchronize their periods
False. Up to 80% of all women believe that it is true, but it is not, according to a study carried out in 2017 by scientists from the University of Oxford. They observed the periods of 360 pairs of women, who either lived together or spent much of their time together. The results showed that the periods were not synchronised. Instead, the opposite: there was a slight tendency towards the women’s periods moving further apart over time.
10. Particle accelerator can wipe out Earth
False. A huge physics experiment in Switzerland might cause a black hole on Earth, but it will not swallow our planet.
When CERN first activated its Large Hadron Collider particle accelerator, the media was full of semi-serious prophecies of the end of the world.
The accelerator was designed to collide protons, and more, at a much greater force than ever before. According to scientists, that could cause a quantum black hole. In the most extreme interpretations, the dark hole would attract more mass, finally swallowing our planet.
However, a commission dismissed the risk. The formation of a quantum black hole requires energies 39 times the level that the accelerator can produce. And if formed, it would immediately disappear again.
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Gonorrhoea bacterium is the world’s strongest organism
Strange but true. It makes sex organs "burn" with pain, but the gonorrhoea bacterium is also very strong.
Boxing experts talk about the power of boxers based on weight classes. If they did the same in the animal kingdom, the winner would neither be the bear nor the elephant, but rather the tiny Neisseria gonorrhoeae, which causes the gonorrhoea venereal disease. Scientists have demonstrated how the bacterium can interlace its individual pili – thread-like appendages that are used for motion – into an ultra-strong rope. And using the rope, it can pull up to 100,000 times its own weight – more than any other organism in the world. If we were just as strong, we would be able to pull as much as 7,000 tonnes. The bacterium uses its amazing powers to hold on to victims.
Shrunken brains love porn.
The brains of men who watch lots of porn are different from those of men who rarely watch porn. A study from 2014 showed that the brain centres that have to do with reward and motivation were generally smaller and had fewer internal connections in porn watchers. However, the scientists were unable to determine whether the shrunken brain was the cause or a result of the high porn consumption.
A cloud weighs 500 t
Clouds fly with the wind, but they are not by any means weightless – 1 cm³ contains about 0.5 g of vapour. Hence, the total mass of even a small altocumulus cloud is close to 500 t. The reason why the clouds are still "flying" is that they are lighter than the air below them, just like a ship is lighter than the water below it.
Written by Niels Hansen in "Australian Science Illustrated", Australia, issue 63, published 15th November, 2018, excerpts pp. 30-37. Digitized, adapted and illustrated to be posted by Leopoldo Costa.
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