1. Professor Xie Piluo found that the whirlpool of bath water always rotates in the same direction. After continuous research, it is related to the autobiography of the earth. (whirlpool of bath water)

2. Boyle, a famous British chemist, dripped hydrochloric acid on violet petals. It was found that it would change color, and after continuous experiments, litmus test paper was invented. (Violet changes color)

I thought that Austrian doctors discovered that their son was dreaming while sleeping through constant observation. Through constant observation, it is proved that people who sleep are really dreaming when their eyes turn. (eye movements during sleep)

4. Newton started from the fall of the apple and constantly studied and found gravity.

When Luban went up the mountain, his hand was scratched by plants and he invented the saw.

6. Edison invented the electric light.

7. Galileo-two iron balls landed at the same time

Watt invented the steam engine.

I hope I can help you!