Solids and liquids have something called a vapor pressure, and it's like a layer of gas of that (m)aterial at its surface. It increases with temperature
Small particles in a gas or liquid constantly (m)ove around randomly. Work on this "Brownian motion" led to the acceptance of atoms as physical reality
I really wish that climate change, vaccines, mask wearing, etc. hadn't become politicized. Our near- and long-term future would be a lot more hopeful (M)