First, the value of popular science knowledge
Popular science knowledge covers all aspects of science, whether it is physics, chemistry, biology or daily life. Because it covers a wide range, it has laid the important significance and influence of popular science knowledge.
The significance of popular science knowledge inevitably requires that our popular science education must keep pace with the times and walk with the quality education we advocate. Let popular science knowledge and popular science education really enter people's lives. The significance and influence of popular science knowledge will be far-reaching and lasting.
Second, the encyclopedia of popular science knowledge
1. Why do the stars twinkle?
We see the stars shining, not because the luminosity of the stars has changed, 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 its density. So when we look at the stars through it on the ground, we will see that the stars seem to be flashing.
2. Why is the squirrel's tail so big?
Don't look at the relaxed mouse tail! When the squirrel jumps around the tree, its tail plays a great role. It can keep balance when the squirrel jumps to the tree to avoid falling and being injured. In addition, this big tail can play a protective role in winter, tightly surrounding the squirrel's body, which is convenient and practical.
3. Why does sorbet get angry?
The reason why sorbet bubbles is because there is a lot of invisible water vapor in the outside air. When it comes to cold sorbet, it will liquefy into droplets when it is cold. It seems that the sorbet is bubbling.
4. 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 supplemented to balance the needs of the body. Because these residual carbon dioxide will affect our body's functional activities, then the body will send out a protective reaction, so we yawn. Yawning is a deep breathing action, which will let us breathe in more oxygen and expel more carbon dioxide than usual, and it can also eliminate fatigue.
5. Why can't the food in cans go bad easily?
Lunch meat, black beans and ketchup beans are all delicious canned foods, which can be preserved for a long time and are not easy to deteriorate. 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 contaminated with a little bacteria, they can't survive or reproduce!
6. Why do babies cry all the time when they are born?
Babies cry when they are born, not because they are unhappy, but because they are taking the first breath of air! When babies leave their mother's body and are born, the first breath of air will rush to their throats, violently impact the vocal cords, make them vibrate, and then make a sound similar to crying.
7. 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 so strong that we can't see the stars.
8. What is thunder?
This is a natural phenomenon that negative electricity meets positive electricity. When it rains, some clouds in the sky are positively charged and some are negatively charged. When two clouds meet, they will discharge, emit bright and bright lightning, and at the same time release a lot of heat, which will make the surrounding air heated, expand and make a loud noise. This is thunder.
9. Why are there fallen leaves?
It's fall here. Leaves evaporate more water than in summer, but roots absorb less water than in summer. In order to reduce the water loss of trees, stem cells began to form separation layers. When the nutrients leave the leaves completely, the separation layer separates the leaves from the trunk and leaves fall off.
10, why does the lizard bounce back when its tail is broken?
In order to protect themselves, many lizards also protect their eyes and ears; When some lizards are attacked, their tails will be broken due to the severe contraction of their muscles. Because there are still some nerves alive in the broken tail, it will keep bouncing, thus distracting the enemy and running away. 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 continue to live.