The plane toilet is a mysterious contraption.

Unlike its grounded cousins, it is far louder when it flushes, complete with a giant woosh of air that will freak out the uninitiated.

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If you've ever been curious as to how plane toilets actually function in the air, the cheery engineers in "The Pee Lab" (seriously) over at Air New Zealand have put together a behind-the-scenes video explainer. 

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You'll find out that planes don't go releasing toilet waste in the sky and onto people's heads, and that a single toilet costs US$17,000. 

That's likely the most expensive receptacle you'll ever have the pleasure of doing your business in, by the way. Anyway, don't just take our word for it -- let these Kiwis show how excited they are about fixing toilets.

[h/tNZ Herald]

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(责任编辑：知識)