How fast do air molecules travel?

Toby - It is certainly true. They're buzzing around very fast in the air. They're buzzing around at about a thousand miles an hour or so, which is not that strange because of course when we think about the speed of sound through air, sound waves travel through air by the little molecules collectively getting together and propagating pressure waves through the air. So the speed of sound is quite closely related to the speed of the molecules.

Chris - And why are they going so fast?

Toby - They're going so fast because they're hot and they're very little. And the hotter they are, the faster they go.

Chris - Because it's not much to accelerate. They don't need much energy?

Toby - They don't need much energy. But I have to say, they don't go very fast in the same direction for very long. I think it's less than a billionth of a second before they hit someone else.