In science, a gas is one of the three states of matter, along with solids and liquids. Gases are all around us, and they can be found in the air we breathe, such as oxygen and carbon dioxide. Gases do not have a definite shape or volume, and they can expand to fill the space available to them. When heated, gases expand even more, and when cooled, they contract.
Some common examples of gases include:
Here are some questions and activities to help you learn more about gases: