Does gas have a shape? When we think of gas, we usually envision a tank, rather than the gas itself. Like maybe a scuba diving (oxygen) tank, or the tank(s) that welders have. We further envision that gas is green, and rises off something that stinks!

That would mean that the shape of gas is cylindrical, with a pointed end! We'll find out if that is really true by doing this project.

Fill a balloon with air and seal the neck with a rubber band. Squeeze the balloon into different shapes. What is the shape of the air inside the balloon?

You will realize that air can be compressed and its shape can be changed. (Every time the balloon undergoes a change of shape, the air in it changes shape too.)

If you repeat this activity with a balloon filled with carbon dioxide, you will realize that gases have no shape of their own -- gases are shapeless -- but they take on the shape of their containers.