CATDOLL : CATDOLL: Science and Technology Knowledge Innovation Handwritten Newspaper

1. Why do stars twinkle?

We see stars twinkling, which is not due to changes in the brightness of the stars themselves, but is related to the obstruction of the atmosphere.

The atmosphere is between us and the stars. 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 according to its density. So when we look at the stars through it from the ground, we see that the stars seem to be flickering.

2. Why do people yawn?

When we feel tired, a lot of carbon dioxide is produced in the body. When there is too much carbon dioxide, oxygen must be added to balance the body's needs. Because the residual carbon dioxide will affect our body's functional activities, the body will then issue a protective response, and yawning occurs.

Yawning is a deep breathing action. It allows us to inhale more oxygen and expel more carbon dioxide than usual, and it also helps to eliminate fatigue.

3. Why can snakes walk without legs?

Snakes have many scales on their bodies, which is the outermost layer of armor on their bodies. Scales are not only used to protect the body, but also can be their "feet".

When a snake crawls forward, its body will be in an S shape. Each scale outside the S shape will be raised to help the snake grip the uneven road surface as it moves forward. These scales work together with the snake's muscles and can push the body forward to crawl, so snakes can move without feet!

4. Why do sunflowers always bloom towards the sun?

The sunflower contains a substance called "auxin" in the stem below the disk. This substance has the function of accelerating reproduction, but it is photophobic and will run to the side away from light when it encounters light.

So when the sun rises, the sunflower stem immediately hides to the side that is not in the light, and it looks like the whole plant is bent towards the sun.

5. Why does a person’s hair turn white as they age?

There is a substance called "melanin" in our hair. The more melanin there is, the darker the hair color will be. If there is less melanin, the hair will turn yellow or white. When humans reach old age, various functions of the body will gradually decline, and the formation of pigments will also become less and less, so the hair will gradually turn white!

6. Why do fireflies glow?

Fireflies can glow because they have a light organ at the end of their abdomen. The light organ is filled with many phosphorus-containing luminescent substances and luminescent enzymes, which enable fireflies to emit flickering light.

Fireflies emit light for purposes other than illumination, such as courtship, warning, and trapping. It is also a tool for them to communicate. Different types of fireflies emit light in different ways, frequencies, and colors, and they use this to convey different messages.

7. Why does your stomach growl when you are hungry?

When you are hungry, your stomach will growl. This is because the food you ate before is almost digested. Although the stomach is empty, the gastric juice in the stomach continues to be secreted. At this time, the contraction of the stomach will gradually expand, and the liquid and gas inside will churn, causing the gurgling sound.

Don’t be embarrassed about your rumbling stomach next time because it’s a normal physiological action.

8. Why can't ostriches fly?

Ostrich is a kind of large bird, but it can't fly! It's not because its wings are useless, but because its feathers are too soft and its wings are too small, which is not suitable for flying. In addition, the muscles of ostriches are not well developed and the breastbone is flat, which is not helpful for flying.

Ostriches live in Africa. As they have lived in desert areas for a long time, their bodies have gradually evolved into their current form in order to adapt to the environment.

9. Why do canned foods not spoil easily?

Spam, dace in black bean sauce, beans in tomato sauce... are all delicious canned foods that can be stored for a long time without spoiling easily. This is because the cans are sealed and bacteria cannot enter.

When people make canned food, they extract all the air from the can and then seal it. In the absence of air, even if there are a few bacteria on the food inside, they cannot survive or reproduce!

10. Why do babies cry non-stop when they are born?

Babies cry loudly when they are born. It’s not because they are unhappy, but because they are taking big gulps of their first breath of air!

When babies are born, the first breath of air they take in rushes to the throat, which violently impacts the vocal cords, causing them to vibrate and produce a sound similar to crying.

11. Why does a lizard's tail continue to bounce after it breaks off?

In order to protect themselves, many lizards also use protective colors to hide from others. When attacked, some lizards' tails will be broken off due to the violent contraction of muscles. Since some nerves in the broken tail are still alive, it will keep bouncing, thus distracting the enemy's attention and escaping. Don't think that their lives will end like this. In fact, it only takes a few months for the tail to grow back and continue to live.

12. Why do squirrels have such large tails?

Don't underestimate the squirrel's tail! When the squirrel jumps on the tree, its tail is playing a very important role. It can help the squirrel to gain balance when jumping on the tree and avoid falling and getting injured. In addition, this big tail can also play a protective role in winter, tightly surrounding the squirrel's body, which is both convenient and practical.

13. Why can't a person's thumb have one or three joints?

Most people have five fingers, and the lengths of their fingers vary. But has anyone noticed that, except for the thumb, the other fingers also have three joints, but the thumb has only two? It turns out that the number of joints is just right to match the other four fingers. If it had three joints, the thumb would appear weak and unable to lift heavier objects; if it had only one joint, it would not be able to cooperate with the other four fingers to grasp things freely!

14. Why don’t we feel itchy when we scratch ourselves?

When someone else tickles us, we feel itchy and laugh constantly; however, when we tickle ourselves, we not only do not laugh, but also do not feel itchy. Because we are mentally prepared, the brain will send a "no danger" message, and the nerves will relax, so we will not laugh or feel itchy!

15. Why is most sea water blue or green?

When you look at the sea, you often find that the seawater is blue or green. However, when you scoop up the seawater, you can only see that it is transparent and colorless like the water in the past. It turns out that the seawater itself is not much different from the water we come into contact with in our daily lives, and it is also transparent. The green color we see is actually a phenomenon caused by the seawater's ability to absorb light. Only green light can be absorbed by the seawater and then reflected; when the seawater is deeper, the green light is also absorbed, and the seawater looks blue.

16. Why do we get goose bumps?

Our skin is covered with sweat hairs, and there is an arrector pili muscle under each pore. When stimulated by nerves (e.g., anger, fear, cold, etc.), the body temperature will drop, and the arrector pili 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 larger than they actually are, thereby scaring off enemies.

17. Are seahorses born from the father’s belly?

Almost all animals reproduce through females, but seahorses are different. They are born through males. On the belly of the male seahorse there is a brooding pouch similar to a kangaroo's "brood pouch". The female seahorse will deposit her eggs into the male seahorse's brooding pouch. After that, the male seahorse will take on the responsibility of breeding. After about three weeks, the baby seahorse will pop out of the father's body.

18. Why do leaves change color?

The reason why leaves change color is related to the chemical substance they contain - chlorophyll. When autumn comes, the daytime is shorter than in summer, and the temperature is lower, so the leaves stop producing chlorophyll, and the remaining nutrients are transported to the trunk and roots for storage. The leaves lack green chlorophyll, and at the same time, other chemical pigments appear, so we see more yellow and brown leaves.

19. Why do leaves fall?

When autumn comes, the water evaporates from the leaves more than in the summer, but the roots absorb less water than in the summer. In order to reduce the water loss of trees, the cells in the stems begin to form a separation layer. After the nutrients completely leave the leaves, the separation layer will isolate the leaves from the trunk, causing the leaves to fall off.

20. Why do whales spout water?

Whales are a type of mammal, but they don't have a nose shell, and their nostrils are on the top of their heads. Living in the water, they breathe with their lungs, which can store a lot of air at a time, and they don't need to frequently come to the surface to breathe. But when they come to the surface to breathe, they breathe through their noses, and the loud sound waves produced by the seawater spraying out of their bodies when they breathe are caused by pressure.