Now, in gas molecules we don't have that because the molecules move at high speeds when they pass each other, they don't really feel too much force, so they don't bond. Let's look at the second thing. So gases are compressible and that's because they take up much less volume than the volume of the container they are in. For example, let's look at this big ball, right? So inside this ball we have air. And if you were to push this guy in, I could easily to some point push this ball in.