Where did the Water Go?

Mrs. McGill's class set up an investigation to learn about evaporation. Students examined the balance and were asked what they thought caused the open cup to go up. They quickly came to the conclusion that it weighed less because the paper towel exposed to air dried out. The lesson learned was that wet materials become dry when exposed to air and the drying process is called evaporation. Water changes into a gas called water vapor and goes into the air.