* Gaseous state: Oxygen molecules are free to move around, bouncing off each other and the container walls.
* High pressure: The oxygen is compressed to a much smaller volume than it would occupy at atmospheric pressure. This means the oxygen molecules are packed closer together.
The pressure inside an oxygen tank is typically very high, often exceeding 2000 psi (pounds per square inch). This high pressure allows a large amount of oxygen to be stored in a relatively small tank.
Important note: Oxygen tanks are not filled with liquid oxygen. That's a separate type of container used for different applications.
