2. Why does the sunflower face the sun?

3. Why can water spiders walk on water?

4. How is the rainbow formed?

5. Do spiders eat dead things?

6. Why do moths put out fires?

7. What is the principle of glow sticks?

8. Why does hot water shrink plastic bottles?

Extended data:

Model essay on scientific papers:

Science is often attractive, science will never be explored, and it will always be fresh and interesting. For example, take floating as an example

Perhaps many people know about the experiment of eggs, but the process of doing the experiment is far more novel than what I heard.

The experiment is simple. There are only four materials: big glass, salt, spoon and eggs. Although simple, you can learn a lot from it.

Knowledge.

I first picked up the kettle, poured half a glass of water into the glass, and then gently put the eggs into the water, and the eggs sank to the bottom in the glass.

After that, it stopped moving, as if it were resting.

Then I put 1 tablespoon of salt, and the eggs didn't move; I began to put the second spoonful of salt, and the eggs were still lying quietly at the bottom of the cup; I am very angry.

After 6 spoonfuls of salt, the eggs did not live up to my expectations and rose a little; Finally, I put 2 spoonfuls of salt and the eggs got up.

A little higher.

I heard that other people's eggs can float in the middle of water, so I took them out and stirred the unmelted semi-finished salt with a spoon.

After adding salt to the bottom of the cup, I slowly put the eggs in. At this time, the eggs kept floating up and down. I waited for a while, chicken.

Still, struggling to surface.

Finally, I poured the remaining 2 spoonfuls of salt into the water, and the eggs gradually surfaced. If I swim freely in a swimming ring, I am naughty.

Press the egg down with your fingers, release your fingers, and the egg will soon float back to the surface.

Why do eggs float? I got something from the computer: when the eggs were first put into clean water, due to the proportion of eggs,

Big, the buoyancy of the egg is less than its own weight, so it will sink to the bottom.

After the salt is released, water dissolves the salt and the specific gravity of water increases.

When the proportion of salt water and eggs is equal, eggs will float in the middle of water; Continue to add salt, when the specific gravity of salt water is greater than that of eggs.

Specific gravity, eggs will float on salt water, and the top of eggs will be exposed to the water.

The teacher told us in class that any object will be buoyed in water, and the size of the object is equal to the volume of boiling water.

Weight, this is the famous Archimedes principle, also known as the law of buoyancy. In fact, science is as bad as physics when you grow up.

I am surprised that this little experiment contains so many theorems that I understand that science is not only used for relaxation and entertainment, but also

We are very important. I secretly made up my mind to study physics and study this interesting science in the future.