Another simple experiment which deals with the elements of earth is making a liquid nitrogen ice cream! Liquid nitrogen is inert, colorless, odorless, non-corrosive, nonflammable, and extremely cold. Nitrogen makes up the major portion of the atmosphere (78.03% by volume, 75.5% by weight). Nitrogen is inert and will not support combustion; however, it is not life supporting. Nitrogen is inert except when heated to very high temperatures where it combines with some of the more active metals, such as lithium and magnesium, to form nitrides. It will also combine with oxygen to form oxides of nitrogen and, when combined with hydrogen in the presence of catalysts, will form ammonia. You can use liquid nitrogen to make ice cream pretty much instantly. This makes a nice cryogenics or phase change demonstration. It’s also just plain fun. Although nitrogen is nontoxic and inert, it can act as a simple asphyxiant by displacing the oxygen in air to levels below that required to support life.

Inhalation of nitrogen in excessive amounts can cause dizziness, nausea, vomiting, loss of consciousness, and death. Death may result from errors in judgment, confusion, or loss of consciousness that prevents self-rescue. At low oxygen concentrations, unconsciousness and death may occur in seconds and without warning. Personnel, including rescue workers, should not enter areas where the oxygen concentration is below 19.5%, unless provided with a self-contained breathing apparatus or air-line respirator. This recipe is for strawberry ice cream. If you omit the strawberries, you can add a bit of vanilla for vanilla ice cream or some chocolate syrup for chocolate ice cream. Feel free to experiment! This recipe makes a half gallon of strawberry ice cream. First, mix the cream, half-and-half, and sugar in the bowl using the wire whisk. Continue mixing until the sugar has dissolved. If you are making vanilla or chocolate ice cream, whisk in vanilla or chocolate syrup now. Add any other liquid flavorings you might want. Put on your gloves and goggles. Pour a small amount of liquid nitrogen directly into the bowl with the ice cream ingredients. Continue to stir the ice cream, while slowly adding more liquid nitrogen. As soon as the cream base starts to thicken, add the mashed strawberries. Stir vigorously. When the ice cream becomes too thick for the whisk, switch to the wooden spoon. As it hardens more, remove the spoon and just pour the remaining liquid nitrogen onto the ice cream to fully harden it. Allow the excess liquid nitrogen to boil off before serving the ice cream