“This is the source of the invisible current.”
“Heat is a bit abstract at our human scale, where you touch something and get a vague sense of whether it is hot or cold. But down here, you really feel what heat is: the motion of molecules, vibrating, twisting, and colliding as if they’re inside a furious ballpit. When these molecules lose heat, they move more slowly and collide less often. When they gain heat, they speed up and smash together with renewed fervor. Temperature is basically the measure of the average speed of these fantastic dancers performing all day.
