perplexus.info :: Science : Falling beer bubbles

Falling beer bubbles (Posted on 2005-01-12)

If you look closely at a glass of freshly poured Guiness (or any beer--but it's easier to see in a dark ale), you'll notice that some of the bubbles are actually falling instead of rising. Explain how this is possible.

Submitted by Ken Haley

Rating: 4.2500 (4 votes)

Solution: (Hide)

The larger bubbles rise faster and tend toward the middle of the glass where there's less friction. This sets up a current in the glass--up in the middle and down along the outside. The downward current carries the smaller (slower rising) bubbles with it.

Comments: ( You must be logged in to post comments.)

Subject	Author	Date
re: maybe	matt	2005-01-23 03:37:46
maybe	alin	2005-01-22 18:29:05
Theory	Larry	2005-01-12 21:14:34
re: Solution	Penny	2005-01-12 17:01:23
Relativity	Michael Cottle	2005-01-12 16:24:47
My theory... (hic)	Erik O.	2005-01-12 15:54:40
Another theory	Federico Kereki	2005-01-12 15:25:35
re: Solution + possible solution	Hugo	2005-01-12 14:25:49
Solution	Penny	2005-01-12 14:18:13

Please log in:

Login:
Password:
Remember me:

Sign up! \| Forgot password

Search:

Search body:

Forums (1)
Newest Problems
Random Problem
FAQ | About This Site
Site Statistics
New Comments (6)
Unsolved Problems
Top Rated Problems
This month's top
Most Commented On

Chatterbox:


perplexus dot info