Which takes up more space: hot air or cold air?
If something takes up a particular amount of time, space, or effort, it uses that amount. 占用 (时间、空间或精力)
Why hot air takes up more space than cold air
Hot air molecules, on average, have more space between them than cool air molecules. Therefore, when you heat air, it expands to allow more space for the molecules. If you then cool the air, it contracts because cool air molecules need less space than hot air molecules.