Experience confirming the existence of molecules.

All substances are made up of molecules. A molecule is the smallest particle of a substance that has its chemical properties. For example, the phenomenon of diffusion is capable of proving the existence of molecules. It consists in mixing substances with each other, mixing is chaotic. The phenomenon of diffusion can be explained by the fact that the molecules of different substances under thermal action are mixed with each other, and, with an increase in temperature, the speed of movement of molecules increases, and hence the rate of mixing.

Example: dissolving sugar in a glass of tea, the warmer the tea, the faster the sugar dissolves. This proves that both liquid and sugar are made up of molecules.