So, being a lifeguard gives you plenty of time to think of intereseting questions about life. Invariably they are about sex or things that come out of your body. This question came up recently: How come sometimes the water makes bubbles while you pee, and sometimes it don’t? Initial observations tend to support the idea that concentration of the urine might have a role, as bubbles usually form better when the pee is a good yellow, and clear pee doesn’t really work.
Although the scientific research is amazingly sparse in this area, current theories are that the bubbles are formed due to detergent-like byproducts of cholesterol metabolism and proteins excreted in the urine. Check out:
http://biowww.clemson.edu/biolab/bubbles.html
for further theories