On Thursday, December 19, 2013 2:48:47 PM UTC-5, TimR wrote:
On Thursday, December 19, 2013 10:34:33 AM UTC-5, wrote:

Sigh, and completely different settup. It's kind of the reverse of a



P-trap.



It's certainly a U-trap though, and even in a plumbing P trap all the water is in the U.



Hmmm.......?

Why don't you think of the design of the two, how they operate
and get back to us. For starters, a bong is not a U trap. It's
not designed to block air/gas flow. It's designed to make air with
burning smoke bubble up through water when pulled via a vacuum.
So to say that because a bong passes smoke as it's designed to do
somehow means that a P trap isn't effective at sealing out gases
makes no sense.