Now that we had an understanding of how water could end up in the air through evaporation, we were seeing the effects of what happens when you cool it down. Not only did water droplets begin to appear in a closed system, but the droplets got bigger and bigger as they were attracted to each other!
We're seeing changes but can't quite see them as they're so small. We turned to some magnetic marbles to really see what happens with water molecules are they cool down and warm up!
Both these investigations have allowed us to predict what we'd see both high up in the atmosphere when there's high humidity and low towards the ground.
So if there's humidity in the air, and it's cooling off and condensing to make clouds on CCNs, then why don't droplets fall all the time? Like why do some clouds grow taller and others stay suspended in the air?