Although foods rarely appear as a gas, I want the student to have a general understanding of how a liquid enters the gas phase. Water or liquid disappears into a gas and the vapor is released into the air. This disappearance is an important aspect of what sets liquids apart from the other phases, thus making a liquid a liquid. This also helps to explain what happens when a liquid sits over time, as it will disappear into the atmosphere.
Gases have no definite shape or size. Gases spread out and have no particular pattern. They spread out to fill the volume they are in. Gases are present in the air even if we cannot see them. The aroma from a food lets us know that gases are present in the air. A gas can be reversed back into a liquid, the gas will cool down and become a liquid. Condensation is the tiny water droplets that are left when air comes in contact with a warmer surface.