Have you ever wanted to send a garbage can to the stratosphere? Well, now you can! All it takes is a two liter pop bottle filled 1/3 full with liquid nitrogen. Screw the bottle top on very tightly and quickly place the bottle in a metal bowl full of hot water. Next, cover with an upside down garbage can and run away like a crazed scientist.
Stand back, wait, and salute your garbage can as it lifts off to the moon!
Click the link to watch "Garbage Can Rocket with Liquid Nitrogen" on YouTube:
The Science:
Liquid Nitrogen is approximately -320 degF which means it rapidly turns from a liquid to a gas when exposed to normal conditions and temperatures. When placed in a bottle and capped, the liquid continues to vaporize and according to the gas laws, the gas takes up more space than the liquid. However, if the space is limited the pressure will start to build. The pressure in the bottle increases rapidly until the bottle fails, causing the gas to spread out inside the overturned garbage can. This rapid increase of pressure acts upon all sides of the garbage can and "launches" it into the air!
Where to buy liquid nitrogen?
Liquid nitrogen can be purchased at an industrial gas supplier or medical gas supplier. You may have to do some searching in your area but these suppliers usually carry oxygen gas for medical use, acetylene gas for welding and liquid nitrogen for medical and agricultural uses. The container you need to carry liquid nitrogen is called a Dewar (find one here) which are quite expensive. Most places will not sell you liquid nitrogen if you don't have a Dewar although some suppliers will rent or loan you one.
How much does liquid nitrogen cost?
Liquid nitrogen is sold by the liter (or gallon) and varies from $0.10 (US Dollars) for bulk purchases up to $5.00 per liter for a small Dewar.
Is liquid nitrogen dangerous?
Yes. It can be very dangerous. Liquid nitrogen is -320 degrees F (-195.75 degrees C) so it can cause frostbite on skin very quickly and can damage eyes, nose, nose, mouth and internal organs on contact. Liquid nitrogen also evaporates very quickly and the ensuing gas takes up more space than the liquid. If the liquid is left in a container that cannot vent off this gas, pressure builds up and a pressure explosion can occur - this is why only an approved Dewar container with a pressure valve and loose lid can be used to transport consumer Liquid Nitrogen.