100,000 Why Popular Science Knowledge Encyclopedia 100

1. Why does it rain?

This is because the water of rivers, oceans, and lakes turns into water vapor when exposed to sunlight. Water vapor rises into the air because the sky is cold, and when water vapor encounters cold air, it becomes small water droplets, Xiaoice crystals and finally clouds.

The small water droplets that make up the cloud are supported by the upper and lower air currents. The small water droplets and Xiaoice crystals in the cloud collide and merge with each other in motion, and some water vapor directly adheres to the surface of the ice crystals, and the Xiaoice crystals will grow, and when the updraft cannot support it, it will fall under the action of gravity, forming various forms of precipitation (rain, snow, hail, etc.).

During the descent, the temperature at low altitude rises, and the ice crystals melt, which becomes rainfall. When some Xiaoice crystals become relatively large ice crystals, they will fall directly to form hailstones.

2. Why does a beautiful rainbow appear after rain?

The sun creeps out after the rain, and a colorful rainbow sometimes hangs in the sky. This is because the air after the rain is very humid. There were also many small droplets of water hanging in the air.

The sunlight shines on these small water droplets, and due to the different refractive indexes, when various colors of light pass through the small water droplets, different degrees of deflection occur, so that various colors are scattered and presented, forming a beautiful rainbow.

3. Why does it thunder?

When the air near the ground is constantly heated and rises, and the cold air in the upper layer sinks, a strong convection is formed, thus forming a towering cumulonimbus cloud, and the water vapor in the cloud rushes everywhere, which will produce static electricity, and the upper end of the cloud will produce a positive charge, and the lower end of the cloud will produce a negative charge, and the ground is a positive charge, and when the charge is neutralized, a large amount of light and heat will be emitted, so that the air will expand in an instant, and the light will be lightning, and the expansion will make a huge sound is thunder.

4. Why doesn't it thunder in winter?

In winter, due to the control of the continental cold air mass, the air is cold and dry, and the solar radiation is weak, the air is not easy to form violent convection, so thundershowers rarely occur, so thunderstorms are rarely seen in winter.

5. Why is the lake water salty and light?

Most lakes are formed by river water infusion. As the river flows, it dissolves some of the salts in the rocks and soil. and bring salt into the lake.

If the lake has an outlet, the salt will be lost with the river water, and the lake will be light. If the lake has no outlet or is not well drained, the salt will slowly settle down and the lake will be salty.

6. Why is the clear sky blue?

Clear skies are blue because of the scattering of sunlight, which hits many obstacles such as oxygen, nitrogen, and many small particles as it enters the Earth's atmosphere.

Among them, the red light has a strong penetrating ability and can directly pass through obstacles to the ground. The penetration of blue light is weak, and when it hits an obstacle, it is blocked in the air, forming a scatter that fills the entire sky, so that the clear sky appears blue.

1.During the day, birds scream in the branches and fly freely in the sky under the blue sky. At night, just like us, rest, sleep, and regain strength, but the sleeping position is different.

2.Sorbet is bubbling because there is invisible moisture in the outside air. When you touch a cold ice cake, it will liquefy into fog droplets and surround the edge of the ice egg roll when it is cold, as if the ice cake is "bubbling".

3.The stems of sunflowers contain wonderful auxins. Once the light hits, it hits the backlit side, and at the same time, the cells on the backlit side multiply rapidly, so the backlit side grows faster than the light-oriented side, causing the optical rotation to bend.

4.The shell (exoskeleton) of the cicada is hard and cannot expand as the cicada grows. At a certain stage, the cicada's exoskeleton restricts the growth of the cicada, and the cicada sheds its original bone multiplication, which is the cicada's metamorphosis.

5.The bees first spit the sweet juice of the flowers into an empty hive, and in the evening, they inhale the nectar into the honey, swallow it again, swallow it again, swallow it again, swallow it again, and swallow it again and again, and it takes 100,240 times to make sweet honey. 6.

We see stars shining, not because of the luminosity of the stars themselves, but because of the blocking of the atmosphere. When starlight passes through the atmosphere, it is affected by the density and thickness of the atmosphere. The atmosphere is not absolutely transparent, and its transparency varies depending on the density.

So when we look at the stars through the ground, we see that the stars seem to be flickering.