The most common misconceptions people

27.04.2013

If a person is thrown into space without a suit, it will explode. Meteors fall to Earth with red-hot. Red Bulls annoying. Coin dropped from a skyscraper can kill a person. These and other errors are very popular and even have a "scientific" explanation.

Biology

The human body in space explodes

In science fiction films often featured a scene where one of the characters is in space without a spacesuit. In this case the victim surely breaks (required with typical cotton, although in a vacuum sound waves do not apply, because there are no particles that could transmit vibrations), and its interior is beautifully scatter in different directions.

Such an outcome seems logical: to withstand the weight of the many kilometers of air inside our body kept at a pressure equal to that which we experience on the outside. That is, the pressure of one atmosphere. In interstellar space, which however molecules are very rare, and so on have appeared without any protection of human no pressure and it must break from the inside.

In fact it is not.

The Human Body — very stable construction, at least to such damage. Let humans and no solid exoskeleton as, for example, insects, but the skin, blood vessels and bones bodies will move from their seats. Although, left without external pressure equalization, several internal organs swell and "swelling" can break some capillaries.

Particularly strong increase in the size of the lungs and digestive organs, as they are filled with gases that a second ago were cool compressed pressure from the outside.

"Free" oxygen quickly leaves the lungs and circulatory system, and the body will begin to suffer from hypoxia.

The ejected into space a person lose consciousness, but before you shut down, it may have time to feel like something inside him begins to boil: at too low pressure contained within the fluid moving in a gaseous state. But to break a man inside the resulting gas can — if only because the body is too many holes and cracks through which it will leak out.




In total, a person mistakenly released into space without a suit, there are about 90 seconds to being back on the ship (although given the rapid loss of consciousness this time reduced to 15 seconds). After fifteen minutes the unfortunate blood begins to boil, in addition, the damaged brain hypoxia will never be able to fully restore its functionality.

Hair and nails grow for some time after death.

A belief which, after the death of the deceased still have some time to grow hair and nails, is very common. Proponents of this hypothesis explain the fact that some of the physiological processes in the body of the dead continue after death.

In fact, extending the nails of the deceased — a visual illusion.

After death, the body begins to rapidly lose fluid and the skin of a corpse shrinks and shrinks. In particular, the compressed fingertips, making the nails look longer.

Believe in life after death can polish comfort in that truth in their beliefs are. Most of the cells are less sensitive to lack of oxygen than brain cells, so that the hypothetical possibility that after cardiac nails continue to grow for a few minutes, still exists.




Bats are blind

Bats are guided in the dark using echolocation — the same mechanism that is used on submarines. Animals emit sounds in the high frequency range (ultrasound) and "catch" their reflections from surrounding objects. If the sound came back quickly — so the obstacle is close, but if he traveled long or do not come back — the space around freely.

Sending a lot of these pulses and carefully analyzing them, the mice can very accurately determine what is around them.

Many people believe that the holders of such perfect "browser" does not need regular eye and vision almost completely atrophied. This is not the case. First, not all bats use echolocation.

Second, even those animals that are actively using this mechanism is quite bearable and guided by sight. Moreover, bats feed on fruit, very well-developed eyes and take on the face, no less space than comparable-sized eyes nocturnal rodents.

The bodies of insectivorous bats much less, but they are fully functional: using eye animals determine its height relative to the ground, assess the size of the major obstacles and searching for the way, focusing on large objects. In addition, evaluating the level of illumination through the eyes, the mouse is determined that it was night and it was time to fly out to hunt.

Red Bulls annoying

Another common misconception about the features of the animals, which became popular because of the bloodthirsty Spanish bullfight. It is believed that the matador "plant" a bull with a red cape, which he brandishes the nose of the animal. Mindful of this particular bull, many people avoid appearing next to a herd of red clothing.

They needlessly worried: Bulls, like most other mammals (excluding primates) have dichromatic vision, that is, they are simply not able to distinguish between red and green.

The ability to see color is determined by the special light-sensitive cells called cones, but rather by how many types of protein opsin these same cones contain.

For example, in the eyes of the people of the Old World monkeys and there are three types of opsin by which we distinguish a few thousand shades (according to some estimates, up to one hundred thousand). The cones birds are four types of opsin, so in terms of birds all people — colorblind.




Color vision bulls are poorly developed, so that the matador's cape for them nothing special stands. A furious animal rights cause sudden movements or thrusts his sword.

Chameleons change color to disguise the environment

The ability of chameleons change color — often the only thing people know about these tropical lizards. And most piously believes that funny reptiles are green, golubeyut or turn black to disguise themselves as better environmental conditions. For a long time, it was common belief among scientists, but recently experts have concluded that the imitation of being nearby twigs and flowers — it's the latter, why do chameleons change color covers.

Lizards change their color sheets due to special cells — chromatophores, which contain granules of different pigments. Chromatophores have complex branched shape, and the pigments may be in process, and in the cell center. A particular color occurs when pigments are located in the appropriate shade of "twigs".

In order to "drive" there pigments chromatophores relax. If it is necessary to collect granules of the colorant in the center of the cell, the contrary, it is compressed.

Observations lizards nature and laboratory experiments show that the repainting in different colors it is necessary, first of all, for temperature control and interact with each other.

Chameleons, like other reptiles, poorly able to maintain a constant body temperature: it can vary quite widely, depending on the temperature of the environment (scientists call this property is a complicated word poikilothermal).

One or another color appears through appropriate pigments, there are, in particular, is melanin.

This pigment is responsible for the darker color covers lizards, as well as dark surfaces absorb more sunlight than light, chameleons turn brown when they are cold.

In addition, using color reptiles inform relatives about their mood.




If the chameleon is ready for a romantic rendezvous, he chooses one shade, and its intention to immediately attack the neighbor proclaims another. Recently, scientists have found that the more complex social structure in a species of chameleons, the more animals change color and the less it is correlated with the color of the surrounding surfaces.

Physics

If you lose a coin from a skyscraper, it can kill a person

Everyone knows that walking on a construction site without a helmet is dangerous — something not even very heavy and can fall on top of her head to break. While a small bolt or nut will be flying from, say, the 15th floor, they start running up such a speed that will be a real danger. Some people believe that the same applies to the very light objects — such as a coin, if they lose a sufficient height to, say, the Ostankino Tower.

In fact, throw coins with skyscrapers possible, without fearing for the lives of others. Due to air resistance coin can be dispersed only to a certain threshold (for example, parachutists who, of course, lots of coins, with a steady flat accelerated free fall on the strength of up to 40 meters per second, while unstable, that is, tumbling to 50 meters per second).

And that's without taking into account wind gusts, which for a small coin very important. The second thing to remember — because of the shape when assessing the risk of the coin to consider only its kinetic energy. It is calculated using the known formula E = m * v2 / 2, where m — is the mass of the object, and v — speed.

When the weather is calm, coin, dropped from the observation deck of the Ostankino TV tower, at best, reaches a speed of 70 kilometers per hour (about 19 meters per second). For coins 50 cents, this corresponds to 26.6 per Joule of energy. For comparison, pistol 9mm bullet at radius has an energy of 350 joules.

Lightning never strikes twice in one place

This belief is certainly not worth the life of one person. Lightning does not strike only once or twice in the same place: some items are downright favorite targets of lightning. This is especially true at higher metal objects that "attract" lightning — in fact, it is based on this fact the action of lightning conductors, which logically should be called lightning rods.

In spire of the same Ostankino tower strikes each year from 40 to 50 lightning.

Even in the absence of a "trap" for the lightning hit them once, say, a tree does not make it a security guarantee. If on a particular area is a storm, all the places of the area can be "attacked" with equal probability.

A lightning strike in a particular location does not affect the probabilities, although such a conclusion seems intuitively wrong: it is misleading even has a special name "error player."

In different hemispheres funnel of water (for example, in the sink) is twisted in opposite directions


In theory, an experiment that proves that the Coriolis force does affect the movement of liquids of any kind on Earth possible.

To do this, fill the water tank is big enough for a round, just in the middle of which there is a tiny hole, cork, and always at the bottom (to manipulation of the tube did not result in disturbance of liquid). A week later, when the water subsides, even the most minor fluctuations, to carefully remove the plug and wait a few hours until the weak Coriolis force will manifest itself.




This experiment was carried out and the results coincide with the expected: the water in the tank swirled in the same direction as the cyclones in a particular hemisphere.
"Be sure to look at when you're wash, in which direction the water swirls" — this phrase must have heard from their friends everyone who went on holiday to Australia, New Zealand or South Africa.

Confidence that the two hemispheres any fluid flows circulate in opposite directions, lingers in the minds of many people since high school — alas, often mention the example of the sink teacher telling about the Earth's rotation and the Coriolis force.

The force of inertia, named after the French scientist who described it Gustave Gaspard Coriolis, really connected with the rotation of our planet and affects the movement of large masses of air and water: streams of storms and cyclones in the southern hemisphere are twisted clockwise, and in the north — against.

However, compared with the rotational processes that we see in everyday life (the same water hole in a sink) The Earth turns on its axis very slowly, and the order of the Coriolis force is much smaller than any of the forces that control the processes of the rotation of objects around us.

Therefore, under normal conditions noted Coriolis effect on the behavior of water in the shell is impossible, and the direction in which the liquid is sucked into the drain depends primarily on how the filled shell and on its shape.

Astronomy

Falling to Earth meteorites red-hot to very high temperatures

In many cartoons and science fiction tapes fallen to Earth meteorites and even the red-hot smoke. Writers such films and most of their viewers believe that the celestial body heats up due to air friction. This process actually takes place: at an altitude of about 100 kilometers above the Earth meteorite before travel in the vacuum of space, is faced with a huge number of molecules of gas.

Collisions with them warm up the outer layer of stone to enormous temperatures, turning the solid rock into a gas, which is immediately carried away by the atmosphere.

The majority (about 90 percent) of meteorites falling to Earth stone, and the stone has a very low thermal conductivity. As a consequence, if a meteorite large enough, the heat from the outer layers does not have time for a few seconds (average 19 seconds) that the body spends in the atmosphere, passed on the inside of the stone.

If he was still quite cold initially, then the center of the meteorite ever be frozen.

At an altitude of 10-15 kilometers a meteorite usually inhibited and begins to fall without the friction material on the environment, then it has a lot of time to the cold center of chilled surface layer.

As a consequence, just fallen meteorite is not hot, but warm or at best, hot. That is, no fire, for example, he can arrange.

These arguments, however, apply only to the bodies of average weight — large meteorites crash into the surface with tremendous speed and explode, so they are cold or hot — does not matter.
The change of seasons is associated with the approach of the Earth to the Sun

This is perhaps one of the most persistent misconceptions.

At first glance, it seems logical that the closer the Earth to the Sun, the more heat and light falls on the planet. Why in this case, there are winter and summer in different hemispheres at the same time, although they are both on the same planet, the proponents of this view can not explain.

The real reason for the change of seasons is less obvious: the world stands out for several seasons because its axis of rotation around the axis is not parallel to the axis of the Earth's orbit around the sun.

The angle between them is constant and is 23.5 degrees. One can imagine that the Earth's axis — is a needle pierces through the planet so that it comes out of the tip of the North Pole and looks relatively "up" and the blunt end sticks out of the South Pole and directed "down."

When the tip of the needle is pointing to the star, in the Northern Hemisphere summer begins.

The sun rises high above the horizon, and its rays fall on the territory north of the equator at smaller angles: that is, they do not slip on the surface, as it were, "resting" in it. The maximum amount of solar energy reaching the Earth when the rays fall vertically, which is why summer is warmer than winter. At equatorial latitudes rays fall perpendicularly all year round, so there are times of the year are released. Summer in the southern hemisphere comes when the tip of the needle pointing away from the Sun.


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