(1) When the hard plastic card is used to dial the plastic comb teeth quickly and slowly with the same force, the vibration speed of the card is different, so the tone of the sound will be different;

(2) Usually the sound we hear reaches our ears through the air;

(3) If you blow hard in the direction of the arrow, the air above the hair has a fast flow speed and a low pressure, which is less than the pressure below the hair, and the hair floats under the pressure difference.

So the answer is: (1) tone; (2) air; (3) The smaller the better.