Three points into the wood: according to legend, Wang Xizhi wrote on the board, and when the carpenter carved, he found that the handwriting penetrated into the board three points (1 cm) deep. Describing calligraphy as vigorous and powerful is more profound and thorough than metaphorical articles or opinions. The source is Zhang Huai's Wang Xizhi's Shu Duan.
Diffusion is not caused by external effects (such as convection, gravity, etc.). ) is not the result of chemical reaction, but is caused by the irregular movement of substance molecules. This random motion is caused by the slight temperature difference between molecules.
Extended data:
Add half a cup of hot water to one beaker and the same amount of cold water to the other beaker. Inject a drop of ink into the bottom of two cups with a dropper and find that the color of the beaker filled with hot water changes rapidly. It shows that the thermal motion of molecules is related to temperature.
In the diffusion movement, we will find that the higher the temperature, the faster the diffusion. When observing Brownian motion, it is also found that the higher the temperature, the more obvious the motion of suspended particles. These events show that the random movement of molecules is related to temperature, and the higher the temperature, the more intense this movement will be.
Baidu encyclopedia-molecular heat sports