Asked by Riley

Why does a narrow strip of paper, attatched to a vent that is blowing air at a steady rate, wave and flap? I havn't taken physics yet but I would like to know the answer this question.
Answered by bobpursley
If it were truly steady, without any "pulses" of pressure, it wouldn't flap. However, fans don't blow at a steady rate, they pump air with blades.