Take the 2-minute tour ×
Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. It's 100% free, no registration required.

On calm days, the water in the toilet looks completely still. But when it's rainy and windy out, the water looks like it moves and pulsates. Why is this?

share|improve this question
2  
The only time I stare at a toilet is when I'm wishing that I was vomiting. –  Carl Brannen Apr 14 '11 at 22:24
add comment

1 Answer

up vote 9 down vote accepted

Any siphon in Your house will be affected in this way. The inside surface (that you can see) is affected by the air pressure in Your house, the other level is connected to the sewer piping system, wich gets his pressure from a vent of the sewer system.

Both pressures can be affected in many ways by the stormy wind, depending where some passages (like windows not really tight) for the air are located , eg at the windward or leeward side of Your house. The vent of the sewer system can develop pressure variations depending on wind speed by some water-aspirator-like action.

So the siphon in Your toilet works as a pressure differential indicator.

share|improve this answer
1  
You know, that's sorta what I thought when I was thinking about the question. Thanks for the answer! –  Jeff Apr 14 '11 at 14:19
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.