Popularization of Science｜Some Interesting Popular Science Knowledge

When you look at stars,

Have you ever wondered why stars twinkle?

Why does sea look blue?

Why leaves change color

Every child is on a journey of growth

There are always a hundred thousand reasons

Promotion of scientific knowledge can help children

To better understand and understand objective world,

Learn to explore society and life scientifically.

8 interesting scientific facts,

Come and see if there's anything you're interested in!

01

Why do stars twinkle?

When we see twinkling of stars, it is not due to a change in brightness of stars themselves, but because it is related to atmospheric occlusion.

The atmosphere is between us and stars. As starlight passes through atmosphere, it is affected by density and thickness of atmosphere. Because atmosphere is not completely transparent, its transparency will change with density.

So when we look at stars through it on ground, we see the stars appear to twinkle.

02

Why do fireflies glow?

Fireflies will glow because they have a light emitter at end of their abdomen, filled with a variety of phosphor luminescent substances and luminescent enzymes, so that fireflies can emit flashes of light.

In addition to illumination, the purpose of fireflies' light is also to court, warn, trap, etc. It is also a tool for them to communicate. Different types of fireflies emit light in different ways, with different frequencies and colors, and they use this to communicate different messages.

03

Why do squirrels have such big tails?

Don't look at squirrel's tail! While squirrel is jumping up and down tree, its tail is doing a lot of work. The tail can balance squirrel while jumping up tree to avoid falling and getting hurt. In addition, this large tail can play a more protective role in winter: it wraps around squirrel's body to keep warm, which is convenient and practical.

04

Why is sea water mostly blue and green?

When looking at sea, you will often find that sea water is blue and green. However, when you scoop up sea water, all you can see is that it is clear and colorless, just like normal water.

It turns out that sea water itself is not much different from water we come into contact with every day, and it is also transparent. The blue and green colors we see are actually result of seawater's ability to absorb light. Green light can be absorbed by sea water and reflected, and when sea water is deeper, blue light can also be absorbed, so sea water looks blue.

05

Why do leaves change color?

The reason leaves change color is due to chemical they contain, chlorophyll. When autumn arrives, days are shorter and temperatures are cooler than in summer, so leaves stop producing chlorophyll and remaining nutrients are transported to trunk and roots for storage. The lack of green chlorophyll in leaves causes other chemical pigments to appear, so we see more yellow and brown leaves.

069

How do bees make honey?

The bees first spit sweet juice from picked flowers into empty hive, at night they suck sweet juice into honey stomach to prepare it, then they spit it out and swallow it again. It takes 100 to 240 hesitation and vomit in turn before it turns into sweet honey.

07

Why do whales vomit?

The whale is a mammal, but its nose lacks a shell and its nostrils grow on top of its head. Living in water, it breathes with lungs that can store a lot of air at a time, so it doesn't need to go to surface of the water often to breathe.

But when he comes to surface of water to breathe, he breathes through his nose, and loud sound waves that are emitted from body when breathing are caused by pressure.

08

Why fallen leaves?

When autumn comes, more water evaporates from leaves than in summer, but roots absorb less water than in summer. To reduce tree water loss, stem cells begin to form a separating layer. After nutrients have completely left leaves, a separation layer isolate leaves from trunk, and leaves will fall off.