What would happen if you poured liquid nitrogen in a hot tub? Well, I asked myself that same question and decided I should try it to find out. The results were just as I expected - there was a whole lot of cloud formations developing all around the house and I ended up with one very cold hot tub.
Supplies for liquid nitrogen experiments
Liquid Nitrogen (see "Where can I buy Liquid Nitrogen below)
Liquid Nitrogen Dewar (container for transporting liquid nitrogen)
Procedure for liquid nitrogen and hot water experiments
Mixing liquid nitrogen and hot water is quite easy - just pour the two together and see what happens! However, it is important to exercise some caution. Never pour liquid nitrogen into a sealed container by itself or with water; it will build up pressure and explode! If you want to see this happen, check out my page and video on "Launching a Garbage Can with Liquid Nitrogen"
Why does liquid nitrogen and water turn to "fog"?
Liquid nitrogen is -320 degrees F (-195.75 Degrees C) so when it is exposed to air or water that is warmer than this temperature it heats up rapidly due to the great temperature differences. In fact, if you pour liquid nitrogen out of the container it is stored in, you will see it boil! As it changes from a liquid to a gas, it builds pressure in a confined space which is why it shoots up out of the containers in the videos. So, is the fog liquid nitrogen fog? No, not really. The "fog" is mostly water vapor that is condensing into droplets. This happens because the cold nitrogen vapor cools the air very rapidly and the air has water vapor in it - this water vapor condenses into tiny droplets and makes a cloud!
Where can I buy liquid nitrogen?
Liquid nitrogen can be purchased an an industrial gas supplier or medial 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). 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 usually sold by the liter and varies from $0.10 (US Dollars) per liter for bulk purchases up to $5.00 per liter for small quantity purchases.
Is liquid nitrogen dangerous?
Yes. Liquid nitrogen can be very dangerous! As a liquid, it is -320 degrees F (-195.75 Degrees C) so it can cause frostbite upon contact with skin and can damage eyes, 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 and a pressure explosion can occur.
Looking for more Liquid Nitrogen Experiments? Check out the Science Experiments page!
Keep on Learning! ~Craig