Take a leak: 7 cool things about pee

Next time you take the dog out to pee, take a stopwatch too.

Researchers at the Georgia Institute of Technology found most mammals take about 20 seconds to empty their bladders, according to a 2013 article in National Geographic.

Dogs’ bladders can hold a little less than half a gallon of pee. Whales’ bladders, for comparison, can hold more than 100 times that.

But researchers found all animals, weighing more than 2.2 pounds, took about the same time to relieve themselves. Bigger mammals just have much, much stronger flow rate.

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Want to know six more pee facts? “Urine” for it:

Pee can power a generator

A group of girls in Lagos created a urine-powered generator at Maker Faire Africa in 2012. The 14- and 15-year-olds created a system that turned 1 liter of pee into six hours of power.

Some turtles urinate through their mouths

The Chinese softshell turtle gets rid of urea — a major ingredient of pee — through its mouth, according to National Geographic. The adaptation means the frogs don’t have to drink as much water to rinse out the urea in their bodies, and this trick has helped them survive.

Ancient Romans used to wash clothes with pee

According to the Smithsonian Magazine, Ancient Romans washed their clothes with urine. The Romans invented flushing toilets and sewers, and when those public bathrooms were full, the pee would be taken to laundromats and put in a tub and — well, you can guess the rest. The ammonia in pee is a natural cleaner (and still used in lots of soaps today), and the Romans called it “chamber lye.”

… And they used urine to brighten their teeth

Ancient Romans also used the ammonia in urine to bleach their teeth, per the Seattle Times. Thankfully, there are less disgusting ways to brighten your smile now.

Some veggies will change your pee’s color

Your pee might turn red or pink if you eat beets. This happens because of the betanin in the vegetable. According to Healthline, this side effect is called beeturia — but it’s perfectly harmless and temporary.

Pee led to the discovery of a scientific element

A German alchemist who thought he could turn urine into gold by boiling it accidentally discovered phosphorus. According to NPR, the glow-in-the-dark substance he discovered would go on to be used in explosives and fertilizers.