Ask A Scientist General Science Archive

name         Bronte
status       student
grade        6-8
location     N/A

Question -   When you click your fingers how does the sound happen, is
it to do with the friction of your to fingers or the slapping of your
finger and hand?
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The friction from your fingers rubbing together can be heard briefly before
the snap, as a whisking sound.  The snap itself is from the impact of your
finger against your palm.

Ryan Belscamper
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The slapping impact, absolutely.
The friction would only make a faint brief rubbing or hissing noise,
and we know we hear more than that.

If your finger broke away quickly enough
from its position locked to the thumb by friction,
then the acceleration of the surface area of the finger
might in principle be able to make a sudden sharp loud noise.
But I am sure that the real break-away is not that abrupt.

And you can try for yourself:
   snap your fingers but be sure the finger misses the palm.
Or insert some padding on your palm, near the base of you thumb.
A band-aid might work.  A folded tissue has some effect for me.
Your thumb and finger are doing the same friction and fast break-away,
but much less sound results.
And only the slapping point of finger on hand has been changed.

Jim Swenson
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