Here's why:
* Gases are compressible: Unlike solids and liquids, gases have large spaces between their molecules. This means that the molecules can be squeezed closer together, reducing the volume they occupy.
* Pressure and volume: When you pump more oxygen into a container, you are increasing the pressure inside. This pressure forces the oxygen molecules closer together, allowing you to fit more oxygen into the same space.
Important note: While you can compress gases significantly, there are limits. At extremely high pressures, the gas molecules will begin to behave more like a liquid, and further compression becomes difficult.
