This process is called condensation. This is what happens when water molecules in the air touch the outside of the cold cup that is exposed to air. Not much air touches the cup in the bag so not much ...

If the cup of cold water is not exposed to air, no condensation will form. The fast-moving molecules of water vapor transfer their energy to the side of the cup which is cooler. This causes the water ...

I decided to use a small cup filled with table salt; rock salt is significantly pricier. In hindsight, it probably wasn't enough. However, the results were immediate, with less condensation ...