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. Dropped from a skyscraper coin 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 open space without a spacesuit. In this case, the victim will certainly breaks (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 interior beautifully 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 which whatever molecules are very rare, and therefore a man found himself without any protection, and nothing crushes it must break from the inside.

In fact it is not. The human body - a very stable construction, at least, to this kind of damage. Suppose that in humans and there is no rigid exoskeleton, such as insects, but the skin, walls of blood vessels and the bones will not allow authorities to move from their seats. Although left without external pressure equalization, several internal organs swell and their "swelling" may break some capillaries. Particularly strong increase in the size of the lungs and digestive system organs, because they are filled with gas, which has a second ago were great compression pressure from the outside.

"Liberated" oxygen quickly leaves the lungs and circulatory system, and the body begins to suffer from hypoxia. Thrown into space a person lose consciousness, but before you shut down, he may have time to feel inside him something boils: pass into a gaseous state with a significant decrease in the pressure contained within the fluid. But to break the man inside the resulting gas can not - at least, because the body is too many holes and cracks through which it will leak out. In total, a person accidentally walk in 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, affected by hypoxia brain will never be able to fully restore its efficiency.

Hair and nails grow for some time after the death of

Belief, according to which after the death of the deceased at 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 cadaver skin dries and shrinks. In particular, the compressed fingertips, because of what the nails look longer.

Those who believe in life after death nail can be comforted by the fact that the truth in their beliefs are. Most cells are less sensitive to lack of oxygen than brain cells, so that the hypothetical possibility that the post-cardiac arrest fingernails continue to grow for a few minutes, is still 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 - hence the obstacle is close, but if he had traveled a long time or do not come back - space close freely. Sending a lot of pulses and carefully analyzing them, the mouse can accurately determine what is around them.

Many people believe that the owners of "navigator" is so absolutely in need of normal eyes and vision almost completely atrophied. This is not true. Firstly, not all bats use echolocation. Second, even those animals that are actively using this mechanism, it is passable and oriented by sight. Moreover, bats that feed on fruit, her eyes developed very well and take on the face, no less a place than the eyes of comparable size nocturnal rodents. Bodies of insectivorous bats noticeably smaller, but they are quite functional: using the eyes of animals determine their height relative to the ground, evaluate the size of the major obstacles in the way and look, focusing on large objects. In addition, evaluating the level of illumination by means of the eye, the mouse is determined that it was night and it was time to take off on the hunt.

Red annoying 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, which he brandishes in front of the nose of the animal. Mindful of this particular bull, many people avoid appearing next to a herd in a red dress. 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 colors.

The ability to see color is determined by the special light-sensitive cells called cones, but rather by how many types of protein-opsins these same cones contain. For example, in the eyes of men and apes of the Old World, there are three types of opsin by which we distinguish a few thousand shades (according to some estimates, up to one hundred thousand). Cones birds are four types of opsin so in terms of birds all people - colorblind. Color vision bulls very weak, so the cloak matador to them nothing special. A rabies in animals result in abrupt movement of the person and injections sword.

Chameleons change color to camouflage under the environment

The ability of a chameleon changes color - often the only thing that people know about these tropical lizards. And most piously believes that funny reptiles green, golubeyut or blackened to better disguise themselves as environmental conditions. For a long time it was common belief among scientists, but recently experts have come to the conclusion that the imitation of being nearby twigs and flowers - this is the last, what chameleons change color covers.

Lizard change color sheets 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. A particular coloration occurs when the respective color pigments are placed in the "branches". In order to "drive" to pigments, chromatophores relaxes. If it is necessary to collect granules of coloring matter in the center of the cell, it is, on the contrary, is compressed. Observations of the lizards in nature and laboratory experiments have shown that the repainting in different colors you need them in the first place, for thermoregulation and interact with each other. Chameleons like other reptiles, ill able to maintain a constant body temperature: it can vary quite widely, depending on the ambient temperature (scientists call this property is a complex word poikilothermic).

A particular coloring manifested through appropriate pigments, among which in particular includes the 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 its intention to immediately attack the neighbor is declared 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 that is not even very heavy can fall from above and struck his head. While a small bolt or nut will be flying from, say, the 15th floor, they acceleration to a speed that will be a real danger. Some people believe that the same is true of the very light objects - such as a coin, if you throw them with enough height, say, the Ostankino Tower.

In fact, to throw coins with skyscrapers can not fear for the lives of others. Due to the air resistance coin can be dispersed only to a certain threshold (eg, skydivers, which, of course, plenty of coins, with a flat, stable freefall accelerated by forces of up to 40 meters per second, while volatile, that is, tumbling to 50 meters per second). And this is 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 evaluation of the danger of coins you need 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 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 bullet caliber 9 mm at radius 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 things 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 over a specified area is a thunderstorm, all the places of the area can be "attacked" with equal probability. A lightning strike to a particular place does not affect on the probability, although this conclusion seems intuitively wrong: it's confusing even has a special name "gambler's fallacy".

The water funnel different hemispheres (e.g., a sink) is twisted in different directions

In theory, an experiment proving that the Coriolis force really affects the movement of liquids of any kind on Earth possible. For this it is necessary to fill with water sufficiently capacious round container, precisely in the middle of which there is a tiny hole plugging stopper, and always below (to the manipulation of the stopper does not lead to disturbance of 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 will show itself. This experiment was conducted, and the results coincided with the expected: water swirled in the container in the same direction as the cyclone in the specific hemisphere. "Be sure to look at, when you wash, in which direction the water swirls" - this phrase probably heard from his friends, anyone who went on holiday in Australia, New Zealand or South Africa. Confidence that in 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 telling about the Earth's rotation and the Coriolis force.

the inertial force, named after the French scientist who described it Gustave Gaspard Coriolis, really connected with the rotation of our planet and affect the movement of large masses of air and water: streams in storms and cyclones of the southern hemisphere are twisted in a clockwise direction, and in the north - against. However, compared with the rotational process, which 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 that govern objects rotation processes around us. Therefore, under normal conditions notice the influence of the Coriolis force 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

falls to the ground meteorites red-hot to very high temperatures

Many cartoons and science fiction tapes fallen to Earth meteorites glow red, and even smoke. Writers majority of such films and their viewers believe that the celestial body is heated due to air friction. This process takes place: at an altitude of about 100 kilometers above the Earth meteorite previously traveled in vacuo outer faces with a lot of gas molecules. Collisions with them heated outer layer of stone to huge temperature, transforming the solid rock in a gas which is carried away immediately into the atmosphere. The majority (about 90 percent) meteorites fall to the ground stone, and the stone has very poor 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), which body holds in the atmosphere transmits the inside of the stone. If he was still quite cold initially, then the center of the meteorite may even be frozen.

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

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 in 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 have to explain can not.

The true reason for the change of the seasons is less obvious: the world stands a few seasons due to the fact that its axis of rotation around the axis is not parallel to the axis of the Earth's orbit around the sun. The angle of inclination between them is constant and amounts to 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 looks as if "up" and the blunt end sticks out from the South Pole and sent "down". When the tip of the needle points to the star, summer begins in the Northern Hemisphere. 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, and this is why summer is warmer than winter. At 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.