The most common misconceptions people

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

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Biology

The human body in space explodes

In science fiction films often featured a scene where one of the characters is in an open space without a spacesuit. At the same time the victim is sure to burst (always with a characteristic cotton, though in a vacuum sound waves do not apply, as there are no particles that could transmit vibrations), and its beautiful interior of scatter in different directions.

Such an outcome seems logical: to withstand the brunt of many kilometers of air inside our body is supported by a pressure equal to that which we experience on the outside. That is, the pressure of one atmosphere. In interstellar space have whatever molecules are very rare, and thus to find themselves without any protection of human and nothing crushes it must break from the inside.

In fact it's not. The human body - a very stable construction, at least to such damage. Suppose in humans and have a rigid exoskeleton, such as insects, but the skin, bone and vascular wall bodies will not move from their seats. Although left without external pressure equalization, several internal organs swell and "swelling" may break some capillaries. Particularly strong increase in the size of the lungs and organs of the digestive system, because they are filled with gases that have a moment ago was great pressure from the outside squeezed.

"Free" oxygen quickly leaves the lungs and circulatory system, and the body begins to suffer from hypoxia. Thrown into space a person loses consciousness, but before you shut down, he may have time to feel inside him something boils: with a significant decrease in the pressure contained inside the liquid move into a gaseous state. But tear gas formed inside a person can not - at least, because the body is too many holes and crevices through which it would leak out.

In total, the man mistakenly released into space without a spacesuit, is about 90 seconds for it to return to the ship (although given the rapid loss of consciousness this time reduced to 15 seconds). After fifteen minutes at the accident begins to boil the blood, in addition, a damaged brain hypoxia will never be able to fully restore its efficiency.

Hair and nails grow for some time after the death of

Believe me, according to which after the death of the deceased had some time to grow hair and nails, is very common. Proponents of this hypothesis to explain this by the fact that some of the physiological processes in the body of the deceased 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 dries out and shrinks the corpse. In particular, the finger pads are compressed, due to which nails look longer.

Believers in life after death, you can nail comfort that truth in their beliefs are. Most of the cells are less sensitive to lack of oxygen than brain cells, so that the hypothetical probability that after cardiac arrest nails continue to grow for a few minutes, yet there.

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 reflection from surrounding objects. When the sound came back quickly - then the obstacle is near when he traveled for a long time or do not come back - space available nearby. By sending a lot of pulses and analyzing them carefully, the mouse can accurately determine what is around them.

Many people believe that the owners of such a perfect "navigator" is not needed under normal eyes and vision is almost completely atrophied. This is not true. Firstly, not all bats use echolocation. Second, even those animals that actively apply this mechanism is quite bearable and guided by sight. Moreover, bats eating fruit, very well-developed eyes and take in the face no less a place than the eyes of comparable size nocturnal rodents. Bodies of insectivorous bats much smaller, but they are quite functional: Through the eyes of animals determined by its height relative to the ground, evaluate the size of the major obstacles and look for the road, focusing on large objects. In addition, evaluating the level of illumination by means of the eyes, the mouse is determined that it was night and it was time to take off on the hunt.

Red irritated bulls

Another common misconception about the features of the animals, which became popular due to the bloodthirsty Spanish bullfight. It is believed that a matador "gets" the bull by using a red cloak, he swings the nose of the animal. Mindful of this particularly bulls, many people avoid appearing next to a herd of red clothing. They are worried in vain: the bulls, like most other mammals (excluding primates) have dichromacy, that is, they are simply not able to distinguish between red and green.

The ability to see color is determined by special light-sensitive cells called cones, but rather by how many types of proteins, these same cone opsins contain. For example, in the eyes of the people of the Old World monkeys and there are three types of opsins, by which we distinguish between thousands of shades (according to some estimates, up to one hundred thousand). Cones birds are four types of opsins, so in terms of birds all people - colorblind. Color vision bulls very weak, so that the matador's cape to them nothing special. A furious animals cause sharp movements of the person and jabs his sword.

Chameleons change color to disguise the environment

Ability chameleons change color - often the only thing that people know about these tropical lizards. And most holy believes that funny green reptiles, golubeyut or blackened to better disguise under ambient conditions. For a long time it was common belief among scientists, but recently experts have concluded that the mimicry by nearby branches and flowers - this is the last, why chameleons change color covers.

The lizards change color covers due to special cells - chromatophores, which contain granules of different pigments. Chromatophores have complex branched form, and pigments can be in process, and in the center of the cell. One or the other coloring occurs when the corresponding shade pigments are located in the "branches." In order to "drive" to pigments chromatophores relaxes. If it is necessary to collect granules of the colorant in the center of the cell, on the contrary, it is compressed.

Observing the lizards in nature and laboratory experiments show that recoloring with different colors need to them, 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 ambient temperature (scientists call this property a compound word poikilothermic).

A particular color is displayed by suitable pigments, there are, in particular, include 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, by using color reptiles inform relatives about his mood. If chameleon ready for dating, he chooses one shade, and his intention to attack the neighbor immediately proclaimed another. Recently, scientists have found that the more complex social structure from 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 can fall from above and struck his head. While small bolts or nuts will be flying, say, from the 15th floor, they acceleration to a speed that will be a real danger. Argued that the same is true for very light objects - such as a coin, if you lose them with sufficient height, say, the Ostankino Tower.

In fact, to throw coins with skyscrapers can not fear for the lives of others. Because of air resistance coin can be dispersed only to a certain threshold (eg paratroopers, who, of course, lots of coins, with a steady flat freefall accelerated on the strength of 40 meters per second, while unstable, that is, tumbling 50 meters per second). And that's without taking into account wind gusts, which for a small coin is very important. The second thing to remember - because of the shape in the risk assessment of the coins you need to take into account only its kinetic energy. It is calculated by the known formula E = m * v2 / 2, where m - is the mass of the object, and v - its speed.

When the weather calm, the 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 50 cents coins in this energy corresponds to 26, 6 Joule. For comparison, pistol 9mm bullet on departure has an energy of about 350 joules.

Lightning never strikes the same place twice

This belief is certainly not worth the life of one person. Lightning does not strike only a few times in the same place: some items are downright favorite targets of lightning. This applies particularly to high-metallic objects that "attract" lightning - in fact, it is based on this fact the action of lightning conductors, which logically should be called lightning rods. The spire of the same Ostankino tower strikes every year from 40 to 50 lightning.

Even in the absence of "traps" for their single lightning hit, say, a tree does not make it into a guarantor of security. If there is a specific area of ​​the storm, all the places of the area can be "attacked" with equal probability. Lightning strike in a particular place does not affect on the probability, though this conclusion seems intuitively wrong: it is confusing even has a special name "player error».

In different hemispheres funnel water (for example, in the shell) is twisted in different directions

In theory, an experiment proving that the Coriolis force really affects the motion of any liquids on Earth possible. To do this, fill the water container with enough space round, just in the middle of which there is a tiny hole, plug cap, and always from the bottom (to the manipulation of the stopper did not lead to the disturbance of the liquid). A week later, when the water subside even the smallest vibrations to gently remove the plug and wait a few hours until the weak Coriolis force manifests itself. Such an experiment was conducted, and its results are in line with the expected: the water in the container twists in the same direction as the cyclones in a given hemisphere.
"Must see, when you wash, which way the water swirls" - this phrase probably heard from his friends, anyone who traveled on vacation to Australia, New Zealand or South Africa. Confidence that different hemispheres any flow of fluids circulating in opposite directions, lingers in the minds of so many people from school - alas, often mention the example of the sink teacher tells 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 storms and cyclones of the southern hemisphere are twisted in a clockwise direction, and in the north - against. However, compared with rotational process that we observe in everyday life (the same water hole in a sink) Earth turns on its axis very slowly, and the order of the Coriolis force is much smaller than any of the forces governing the process of rotation of objects around us. Therefore, under normal conditions to observe the influence of the Coriolis force on the behavior of water in the sink is not possible, 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

Many cartoons and science fiction tapes fallen to Earth meteorites glow red, and even smoke. Writers of such films, and most of their audience believe that a celestial body is heated by friction with the air. This process actually takes place: at an altitude of about 100 kilometers above the Earth meteorite before travel in the vacuum of space, confronted with a large number of gas molecules. Collisions with them warm up the outer layer of stone to enormous temperatures, turning solid rock into a gas which is immediately carried away by the atmosphere.

The majority (about 90 percent) fall to the ground meteorites 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 (on average, 19 seconds) that the body spends in the atmosphere is transmitted inside of the stone. When he was still quite cold initially, the center of the meteorite ever be frozen.

At an altitude of 10-15 km a meteorite usually inhibited and already begins to fall without a substantial friction of the atmosphere, that he has plenty of time to cool the center of chilled surface layer. As a result, the newly fallen meteorite is not hot, but warm or at best, hot. That is, no fire, for example, he can arrange.

These considerations, 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 is this winter and summer there are in different hemispheres at the same time, although they are both on the same planet, the proponents of this view can no longer be explained.

The real reason for the change of seasons is less obvious: the world stands a few seasons due to the fact that the axis of its rotation 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 - a needle, puncture through the planet so that its tip emerges from the North Pole and looking conditionally "up" and the blunt end sticks out of the South Pole and sent "down».

When the tip of the needle points 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, "abut" in it. The maximum amount of solar energy reaching the Earth when the rays fall perpendicularly, which is why summer is warmer than winter. In equatorial latitudes rays fall perpendicularly to the year-round, so there are times of the year are not allocated. Summer in the southern hemisphere comes when the needle tip is directed away from the sun.

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