Purchase liquid nitrogen from a welding supply shop. Sometimes they will not sell liquid nitrogen in small quantities (less than 50 gallons), so if that is the case contact the physics department of a nearby college. They will often give some to you free of charge.
Store the liquid nitrogen in a thermos with a 1/4 inch hole drilled in the top. Liquid nitrogen is constantly boiling at room temperature, so the thermos could explode without the hole. You may need two thermoses if yours is too small.
Put on your goggles and pour the liquid nitrogen from the thermos into the pan. Fill the pan about 3/4 of the way to the top.
Blow up a balloon fairly full of air and tie it off at the top.
Put on the gloves. Liquid nitrogen is very cold and can cause severe burns.
Place the balloon in the liquid nitrogen. It will begin to shrink as the air inside liquefies. Once it is small enough, shake the balloon to feel the liquid. You may even be able to see it through the wall of the balloon.