Condensation is the change in phase of a gas upon the surface of a solid due to its loss of energy to that solid. Water droplets often form on the surface of cool substances because the water vapor in the air loses energy when it comes into contact with the cold substance and turns to a liquid.
Have you ever taken a soda out of the refrigerator and left it out on a table for a while? You'll notice it's going to start to bead up and water is going form on the outside of that right? Well that is condensation right you've just witnessed a phase change water's change from the gas to water vapor in the room around you to a liquid form those droplets that are running down the can and then forming a little pool below the can so let's talk about the Physics of condensation.
So let's say we've got our cold can right here and we've got these water vapor molecules and they've got a lot of energy and they come in contact with this cold can. They're going to lose some of the energy they're going to give that energy up to the can and when they do that when they lose that energy they're going to go from being a gas high energy form of water to water to to liquid and they're going to form the droplets we see on the sides of the can so what we can see is, there's actually a decrease in entropy and the free energy of the water molecules.
Now conversely, if we're seeing condensation occur on the can the water vapor gas is losing energy the water or the liquid in the can is actually gaining energy so what condensation does is it causes an increase in temperature of the object that's where the water vapor is forming on and we can see this if you've ever been burned by steam it's a lot worse than being burned by hot water because not only is steam very hot water coming on your skin but it's also condensing and it's, it's actually passing on more of that energy into your tissue and its much more severe than just a water burn. Water which is kind of tends to evaporate which actually takes the heat or the energy away from your skin so this is an example of how when something condenses it's actually the energy from the gas is being passed into the object the cooler object that is causing the condensation.