Someone didn't leave the faucet turned off all the way, so there is a slow but steady leak (i.e.

physics/faucet New

New entry, edited from material collected for the archive and not yet in a released version.

Problem

Someone didn't leave the faucet turned off all the way, so there is a
slow but steady leak (i.e. not a drip).  Can you explain why the stream
of water gets narrower as it gets further away from the faucet?

Show solution

The key here is that the stream is steady, which means that at any given
point, the volume of water passing through a cross-section of the stream
is a constant.  Since water accelerates (due to gravity) as it falls, the
speed increases, so in order for the volume to remain constant, the cross
section area must decrease.

-- Walter Prager <wprager@Newbridge.COM>