A friend and I were talking about how windy it’s been, and jokes about the water in the toilet came up. I mean in Wyoming, it can really rock and roll in there. I had to finally find out why.

A physics website calls the whole system, "A siphon, and any siphon in the house can be affected like one." I thought I was getting it, up to that point, but my reading from there was faster than I could comprehend. I was lost after that next part - something to do with the sewer piping system, pressure, and differential, etc...

I guess I wasn’t fluent in physics enough to follow along without someone drawing me a picture. Believe it or not, a guy on mental floss.com had an answer to the question on toilet water and wind. He just made more sense.

Floss-man pointed out there’s a pipe that runs up and out to the roof. This outlet is called a “vent stack.” I could imagine why we'd want a vent here – and that also allows air to move through the pipes.

When the wind blows, the same thing that gives planes lift is in action in the toilet. In the pipes a slight suction effect is pulling on water in the toilet below. Upon reading this I felt like I was gaining on the concept.

Another geek using the handle desertsun41 on city-data.com also made it so I could understand. “On your roof there is a 4" vent stack. If you ever blow across a soda or beer bottle you can make a whistling sound." (Wow, a light just went on as he continued about wind.) "It will also create a little bit of a pressure on the water inside your toilet bowl."

Okay, I really thought he had me there, then, “A volume of water inside performs the same function as a P trap under your sink. That little bit of positive pressure will cause the water to move ever so slightly in the bowl.

Darn it! I was suddenly lost again. Why did he have to go back to using scientific words like "volume, positive pressure and P trap."

Well, the whole thing is a Pee trap, isn’t it?