Video Transcript

My name is Derek Hullinger. I have a PhD in physics, and I'm going to explain a little bit about what condensation means. So one thing that we learned about for example in chemistry is that different substances can be solids or they can be gases or they can be liquids so let's say that we've got water for example. If water is a liquid and it turns in to a gas, we call that evaporation. Right and it's just a matter of the molecules in the liquid disassociating themselves from each other and being free to float around all over and when this happens on Earth then those water molecules join the air and get intermixed with the air and become water vapor in the air. Well the opposite can also happen. Sometimes you have molecules of water that are in the air mixed around and they gather together and they form droplets of water. So that's when gas goes the other direction and turns in to a liquid and that's called condensation. And we see a lot of examples of this all around us. For example if you wake up early in the morning and you go out and look at your lawn you might see drops of dew on the grass. That's condensation of vapor from the air turning in to liquid water. Or you might see it on your windshield in the morning.