Answer:
The practical evidence for the continual motion of molecules is Brownian motion. Brownian motion is the random movement of particles suspended in a fluid (liquid or gas) as a result of collisions with atoms and molecules in the fluid1. This phenomenon was first observed by Robert Brown in 1827, and later explained by Albert Einstein in 19052. Brownian motion can be directly observed using microscopes, cell phones, and computer models2. It can also be used to model the behavior of ideal gases, which are composed of molecules that move randomly and collide elastically3. Brownian motion demonstrates that molecules are not static, but constantly moving and interacting with each other.