ROANOKE, Va. – In order to make a cloud in a jar, you need a few simple things. Make sure you fill it up about halfway with very hot water. Once you do that, take a few ice cubes and put them on top of the jar’s lid. The hot water at the bottom rises into the cooler air from the ice cubes, and condensation begins. However, in order to get a cloud you need to add hairspray.