sorbet bubbles because there is a lot of invisible water vapor in the outside air. When it comes to a very cold sorbet, it will liquefy into droplets and surround it when it is cold. It seems that the sorbet is "bubbling". 5. Why do sunflowers always face the sun?
The stem of sunflower contains a wonderful auxin. This auxin is very afraid of light. When it is irradiated by light, it will go to the backlight side, and at the same time, it will stimulate the cells on the backlight side to multiply rapidly, so the backlight side will grow faster than the light side, which will make the sunflower bend phototropically. 6. Why do cicadas molt?
The shell (exoskeleton) of cicada is hard and can't expand with the growth of cicada. When the cicada grows to a certain stage, the exoskeleton of cicada restricts the growth of cicada, and the cicada takes off the original exoskeleton, which is cicada slough. 7. How do bees make honey?
The bees spit the collected sweet juice of flowers into an empty hive, and at night, they suck the sweet juice into their honey stomachs for modulation, and then spit it out and swallow it, so it takes 1 to 24 times to make sweet honey. 8. Why do the stars twinkle?
We see the stars shining, not because the luminosity of the stars themselves changes, but because of the occlusion of the atmosphere. The atmosphere is between us and the stars. When starlight passes through the atmosphere, it will be affected by the density and thickness of the atmosphere. The atmosphere is not absolutely transparent, and its transparency will change according to the density. So when we look at the stars through it on the ground, we will see that the stars seem to be flashing.
9. Why do people yawn?
when we feel tired, a lot of carbon dioxide has been produced in our bodies. When there is too much carbon dioxide, oxygen must be added to balance the body's needs. Because these residual carbon dioxide will affect the functional activities of our body, then the body will send out a protective reaction, so it yawns. Yawning is a deep breathing action, which will let us breathe in more oxygen and expel carbon dioxide than usual, and also eliminate fatigue.
1. Why can snakes walk without feet?
snakes have many scales, which is the outermost layer of armor. Scales are not only used to protect the body, but also to be their "feet". When a snake crawls forward, its body will be S-shaped. And every scale outside the S-shape will tilt up to help the snake catch the uneven road when it moves forward. These scales cooperate with the snake's muscles and can push the body forward, so the snake can walk without feet!
11. Why does hair turn white when people get old?
There is a substance called melanin in our hair. The more melanin, the darker our hair will be. If there is less melanin, the hair will turn yellow or white. When human beings reach old age, the various functions of the body will gradually decline, and the formation of pigments will be less and less, so the hair will gradually turn white! 12. Why do fireflies glow?
Fireflies glow because there is a light emitter at the end of their abdomen, which is filled with many phosphorus-containing luminescent substances and luminescent enzymes, so that fireflies can emit flashing light. The purpose of fireflies is not only to illuminate, but also to courtship, vigilance, trapping and other purposes. This is also a communication tool for them. Different kinds of fireflies emit light in different ways, frequencies and colors, so they can convey different messages.
13. Why do you growl when you are hungry?
when you are hungry, you will purr. This is because the food you have eaten before is almost digested, and although your stomach is empty, the gastric juice in your stomach will continue to secrete. At this time, the contraction of the stomach will gradually expand, and the liquid and gas inside will be stirred up, causing a purring sound. Don't feel embarrassed about your stomach growling next time! Because this is a normal physiological action.
14. Why can't ostrich fly?
a kind of huge ostrich, but they can't fly to the sky! This is not because their wings are useless, but because their feathers are too soft and their wings are too small to fly at all. In addition, the ostrich's muscles are underdeveloped and its sternum is flat, which is not helpful for flying. Ostrich live in Africa, and because they have lived in desert areas for a long time, their bodies have gradually evolved into what they are now in order to adapt to the environment.
15. Why can't food in cans go bad easily?
Lunch meat, black bean and tomato sauce beans are all delicious canned foods, which can be stored for a long time without spoiling easily. This is because the can is sealed, so bacteria can't enter. When people make canned food, they pump all the air out of the canned food and then seal it. In the absence of air, even if the food inside is stained with a little bacteria, they can't survive or reproduce!
16. Why do babies cry all the time when they are born?
babies will cry when they are born, not because they are unhappy, but because they are taking their first breath of air! When babies leave their mother's body and are born, the first breath of air they breathe will rush to their throats, which will violently impact the vocal cords, make them vibrate, and then make a sound similar to crying.
17. Why does the lizard's tail keep bouncing when it is broken and backward?
In order to protect themselves, many lizards also use protective colors to hide their eyes and ears. When some lizards are attacked, their tails will be broken due to the severe contraction of muscles. Because some nerves are still alive in the broken tail, it will keep bouncing, thus distracting the enemy and escaping. Don't think that their lives will end like this. In fact, it only takes a few months, and their tails will grow back and move on. 18. Why is the squirrel's tail so big?
don't look at the tail of Easy Mouse! While the squirrel is jumping around the tree, its tail is playing a great role. It can balance the squirrel when jumping on the tree and avoid falling and being injured. In addition, this big tail can play a more protective role in winter, tightly surrounding the squirrel's body, which is convenient and practical. 19. Why can't a person's thumb have one or three knots?
The average person has five fingers, and the length of each finger is different. However, is anyone aware that besides the thumb, other fingers also have three sections, while the thumb alone has only two sections? It turns out that its number of joints just matches the other four fingers. If it is three knots, the thumb will appear powerless, so that it can't lift heavy objects; If there is only one section, it can't freely cooperate with the other four fingers to grasp things!
2. Why don't you feel itchy when you scratch yourself?
when others scratch ourselves, we feel itchy and laugh constantly; However, when we scratch ourselves, we not only don't laugh, but also don't feel itchy. Based on our mental preparation, the brain will send a message that there is no danger, and the nerves will relax, so we won't laugh and feel itchy!
21. Why is the sea water mostly blue and green?
looking at the sea, we often find that the sea water is blue and green. However, when you pick up the sea water, you can only see it as transparent and colorless as the old water. It turns out that seawater itself is not much different from the water we come into contact with every day, and it is also transparent. The green color we see is actually a phenomenon produced by the ability of seawater to absorb light. Only green light can be absorbed by seawater and reflected; When the sea water is deeper, the green light is also absorbed, and the sea water looks blue.
22. Why do you get goose bumps?
There are hairs on the surface of our skin, and there is a vertical hair muscle under every pore. When we are stimulated by nerve (for example, angry, afraid, cold, etc.), the temperature of our body will drop, and the vertical hair muscle will contract and make the hair stand up, forming goose bumps. In addition to keeping warm, this physiological system can also make animals look bigger than they really are, thus scaring off enemies. 23. The hippocampus was born in the belly of dad?
Almost all animals are females, but the hippocampus is different. It is born by males. On the belly of the male seahorse, there is an incubator like a kangaroo "pouch", and the female seahorse will discharge the eggs into the incubator of the male seahorse. Since then, the male hippocampus has taken on the responsibility of pregnancy. After about three weeks, the baby hippocampus will pop out of the father's body. 24. Why do leaves change color?
The cause of leaf discoloration is related to the chemical substance-chlorophyll. When autumn comes, the days are shorter than those in summer, and the temperature is lower, so leaves stop producing chlorophyll, and the remaining nutrients are transported to trunks and roots for storage. The leaves lack green chlorophyll, and at the same time, other chemical pigments appear, so we often see yellow and brown leaves. 25. Why are there fallen leaves?
It's time for autumn. The leaves evaporate more water than in summer, but the roots absorb less water than in summer. In order to reduce the water loss of trees, the stem cells begin to form a separation layer. When the nutrients leave the leaves completely, the separation layer will isolate the leaves from the trunk and the leaves will fall off.
26. Why do whales spray water?
A whale is a kind of mammal, but its nose has no nose shell, and its nostrils grow on the top of its head. Living in the water, it breathes with its lungs, and can store a lot of air at one time, so it doesn't need to go to the surface to breathe frequently. But when it breathes to the surface of the water, it will breathe through its nose, and when it breathes, the huge sound waves emitted by the sea water are caused by pressure. 27. How big is the Milky Way? Many perseverances are combined to form a huge galaxy, and the galaxy where the solar system is located is called the Milky Way. The Milky Way is like a big discus, with a width of about 8, light years, a center thickness of about 12, light years, and a total of more than 1, stars. 28. Why can't you see the stars during the day?
Because part of the sunlight is scattered by the gas and dust in the atmosphere during the day, the sky is very bright, and the light radiated by the sun is very strong, so we can't see the stars. 29. What celestial bodies are there in the solar system? There are nine planets in the solar system. They are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto. In addition, there are many asteroids, comets and meteors in the solar system, and there are 2958 officially numbered asteroids. The most famous comet is Halley's comet. How high is the blue sky?
"blue sky" is actually the earth's atmosphere. The atmosphere surrounds the earth's air, which is divided into five layers according to the air density, with a total thickness of 2-3 kilometers. But most of the air is concentrated from the ground to the place below 15 kilometers high, and the higher the air, the thinner it becomes. How thick the atmosphere is, how high the blue sky should be.
31. What's with the thunder?
a: this is a natural phenomenon that negative electricity and positive electricity meet together. When it rains, some clouds in the sky have positive electricity and some have negative electricity. When the two clouds meet, they will discharge, emit bright and bright lightning, and at the same time release a lot of heat, so that the surrounding air will be heated, expanded and make a loud noise. This is thunder. 32. Why can an airplane fly into the sky?
a: the plane has two wings, just like the wings of a bird, and it also has a propeller. The wing can generate lift and lift the plane in the air; Propeller can produce the ability to push the plane forward. Therefore, the plane can fly into the sky like a bird. 33, hanging on the wall of the quartz clock, when the battery runs out of power and stops walking, its second hand often stops at the position of "9" on the dial. This is because the second hand is most hindered by the heavy torque at the "9" position.
34. The "combustion" of electric furnace is the conversion of electric energy into internal energy, without oxygen, which can only oxidize the electric furnace wire and shorten its service life. 35. When there is cold water in the pot, the water droplets attached to the outer surface of the pot bottom can only be dried up on the flame for a long time, and they will not boil until they are dried up. This is because the water droplets, the pot and the water in the pot keep heat conduction, and the temperature is almost the same. As long as the water in the pot is not boiled, the water droplets will not boil, and the water droplets will be gradually dried up by evaporation on the flame. 36. There are several small holes on the side of the gas nozzle of the natural gas furnace, but the natural gas will not be from the side. Only from the nozzle. This is because the gas flow velocity at the nozzle is high, and according to the principle of fluid mechanics, the gas flow surface pressure is lower than the atmospheric pressure outside the side hole, so the gas will not be ejected from the side hole of the nozzle. 37. The mirror that is out of shape, the farther away from the mirror, the more out of shape. Because the image in the mirror is formed by the reflection of the silver-plated surface behind the mirror, the uneven silver-plated surface or uneven glass thickness will produce aliasing. Out-of-shape mirror, the farther a person is from the mirror, the more the reflected light on the silver-plated surface deviates from the normal position according to the principle of light amplification, and the more out-of-shape the mirror is. < P > 38. Mantis is called "the magic knife-catcher" 39. In Uganda, Africa, there is a kind of mouse that can eat cats. This kind of mouse is similar to ordinary house mouse, except that it has a hard shell on its mouth and grows very hard. This kind of mouse can give off a strong smell, and the cat will be paralyzed, trembling and unable to move after smelling it. At this time, the mouse jumps over, bites the cat's throat with sharp teeth, sucks up all the blood, and then drags the cat to a hidden place and eats it slowly. 4. A wenbird in the Amazon river basin, when its companion died unfortunately, other similar birds would pick colorful petals and green leaves and scatter them on the companion's body for "flower burial", and each one hung his head to express his mourning for the deceased.
41. Why is the sky red in the morning and evening? In the morning and evening, colorful clouds often appear on the horizon before and after sunrise and sunset. The formation of morning glow and sunset glow is due to the scattering of light by air. When sunlight enters the atmosphere, it will scatter when it meets atmospheric molecules and particles suspended in the atmosphere. These atmospheric molecules and particles themselves do not emit light, but because they scatter sunlight, each atmospheric molecule forms a source of scattered light < P >. According to Rayleigh scattering law, the light with shorter wavelength such as purple, blue and cyan in the solar spectrum is most easily scattered, while the light with longer wavelength such as
red, orange and yellow has strong light transmission ability. Therefore, we see that the clear sky is always blue, while the light above the horizon is only yellow, orange and red with longer wavelength. After these rays are scattered by air molecules and water vapor and other impurities, the sky there takes on a gorgeous < P > color. 42. Why is a bottle filled with water not easy to break?
There are two identical glass bottles, one is empty, the other is filled with water, and they fall to the ground from the same height at the same time. Which bottle is easy to break? Generally speaking, heavy bottles are easy to break. However, when the bottle is filled with water, the water in the bottle has another function, which can reduce the deformation of the bottle and make it difficult to break. The breakage of glass bottles is mostly caused by deformation. When the empty bottle falls to the ground, it constantly exerts a pressure on the bottle, which deforms from the outside to the inside and finally breaks. The bottle is filled with water. Because water is incompressible, the deformation is reduced and the bottle is not easy to break. The bottle is filled with water, and then the cap is tightened, so it is more difficult to break. 43, spicy food