Whoosh! A loud sucking sound comes from an airplane toilet when you flush it. Did you ever wonder what happens to the waste?
The Back Story
- Contrary to popular belief, an airplane toilet doesn’t just dump the waste in the sky—not even at a typical cruising altitude of 12,000 meters (about 39,000 feet).
- The waste actually goes from the toilet to a storage tank in the airplane. Once the plane lands, the tank is drained, ready to be filled again on the next flight.
- What’s interesting is how airplane toilets flush. They don’t use gravity and a lot of water, like most toilets on the ground. A different principle explains how airplane toilets work, and it involves air pressure.
- Watch this entertaining video for a dramatic demonstration of how an airplane toilet flushes: http://science.discovery.com/tv-shows/outrageous-acts-of-science/videos/monster-flush.htm
Can You Apply It?
Learn more about airplane toilets at the links below. Then answer the following questions.
- Why can’t you use gravity and a lot of water to flush an airplane toilet as you can a toilet on the ground?
- Describe how an airplane toilet works.
- How does air pressure explain how an airplane toilet works?
- Why is the air pressure so low outside an airplane at cruising altitude?