Think you are conflating just random pool balls, and particles with properties. If a few hydrogen and oxygen atoms get together and form water. That is expecte

Think you are conflating just random pool balls, and particles with properties. If a few hydrogen and oxygen atoms get together and form water. That is expected, even if they are bouncing around randomly. This occurs at many different scales. There is random motion of particles of air in a room, but the overall 'pressure' can be measured and be constant.