To make a snow cone with nitrous gas, as an experiment, you will need the following: liquid nitrogen, protective gear, a bell jar, and a dish to hold the liquid nitrous. While wearing protective equipment, pour liquid nitrogen into a dish. Place it in a bell jar. Now, turn on the vacuum, until it freezes. The snow only lasts for a small bit of time, because it melts immediately upon having contact with the air. When you turn the vacuum off, it will immediately melt. When you turn it on, it will freeze again, behaving the way popcorn does in a popcorn maker. This demonstrates the states of matter.