Join 3,561 readers in helping fund MetaFilter (Hide)


What makes pee foamy?
January 5, 2009 8:49 PM   Subscribe

What makes pee foamy?

It has to be more than just liquid-on-liquid action. I'm guessing viscosity will be mentioned in the answer.
posted by hootch to Health & Fitness (14 answers total)
 
Proteins in urine make it foamy, just like the proteins in milk let you foam milk. In fact one symptom of certain kidney problems is excessively foamy urine.

NOTE: Attempting to stare at your own urine in order to diagnose medical conditions is not a good idea.
posted by Justinian at 9:01 PM on January 5, 2009


Same thing that makes the ocean foamy. Protein.
posted by dead cousin ted at 9:19 PM on January 5, 2009


Here ya go.
posted by dead cousin ted at 9:20 PM on January 5, 2009


Btw, I just googled foamy urine to get that link, might help you out for future questions.
posted by dead cousin ted at 9:23 PM on January 5, 2009


Protein. If you are male, it could be a the result of an earlier retrograde ejaculation (semen in your bladder) or a problem with your kidneys.
posted by zippy at 9:24 PM on January 5, 2009


More generally, dissolved organic carbons, including proteins, amino acids, and other carbon based substances...
posted by nonliteral at 9:39 PM on January 5, 2009


I think it's probably albumin, to be specific.
posted by Chocolate Pickle at 10:15 PM on January 5, 2009


(Oops, I'm wrong.)
posted by Chocolate Pickle at 10:16 PM on January 5, 2009


If you are male, it could be a the result of an earlier retrograde ejaculation (semen in your bladder) or a problem with your kidneys

Or a UTI (urinary tract infection). Men get them too.
posted by kisch mokusch at 10:33 PM on January 5, 2009


It may be the surface tension. I'm basing this on a video I saw by Robert Krampf, but unfortunately I can't share it since he has raised a paywall.
posted by daboo at 12:16 AM on January 6, 2009


aqueous dissolved proteins = correlated rise in surface tension = more foaminess
posted by telstar at 12:37 AM on January 6, 2009


Well, let me give this a shot. I'm an engineer, not a chemist, but ...

You know how if your brother asks you for some water, you can pour just a little more water into his glass than it can hold, and it's hilarious? This is a result of Surface Tension: the water molecules are attracted to each other a more than they are attracted to the air molecules, so the water molecules tend to cluster together in a shape that minimizes their surface area. This is why, for example, water tends to bead up on wax paper. If you want to take a water droplet and maybe stretch it out a little bit (increasing the surface area), it costs energy.

OK, so making surfaces costs energy. What surfactants do is lower the cost to create new surface.

You know those water striding insects? The ones that 'walk' on the surface of water? They are taking advantage of this 'surface tension'. Imagine you put a little bit of liquid soap (soap is a surfactant) next to them. The insects will no longer be able to 'walk' on the water because the surface tension is lowered. Obviously this is a very cruel thing to do to the insects, so just imagine it. Or use a bit of paper.

Now proteins are (kind of) surfactants. So proteins are lowering the cost of creating surfaces in your pee. Foams are a lot of surface (as you can imagine), so proteins in your pee can let it form a lot of surface, and hence, foam.

Hopefully this helped.
posted by Comrade_robot at 6:45 AM on January 6, 2009


Protein in the urine is not normal, by the way.
posted by gramcracker at 7:49 PM on January 6, 2009


Here's what *I* want to know, though - how come it's foamy some times, but not others?
posted by Afroblanco at 9:35 PM on January 6, 2009


« Older What is the difference between...   |  D/s filter: Should I be concer... Newer »
This thread is closed to new comments.