So if water can evaporate into the air, is it possible that the water in the air can "relocate" somewhere else, like onto the outside of a cup seen here? We've all had this experience, where water "appears" on the outside of a cold cup. We're recognizing a couple things, as we think about this. Some of our cold cups in our cup investigations experienced this more so than others. We seem to see this when there's a big difference between temperatures...kind of like the cooler air above our hot cups in our hot cup tests. Is this phenomenon reversing? |
So with some really cold water inside some cups, and the humidifiers on HIGH (it's super dry here in Colorado), we saw a slight increase in weight. From 460.4g -->460.7g for the plastic cup and from 582.2g -->582.4g for the metal cup. This was interesting to us because if the water was coming from the inside of the cups to the outside, the weight would have stayed the same, but it didn't. It went up!
Some of us were still skeptical, so we put some food coloring in some other cups and saw what color the droplets appeared on the outside. Over time, we saw the outside droplets were clear, not the color of the dye. This gave us further evidence that the water in the air was landing on the cups.
SO this is interesting...we've got water in the air attaching to the outside of a cup. What exactly is going on to allow this condensation to happen. Like how are the particles moving? Why does this phenomenon happen?