We investigated how to turn salt water into fresh water as part of our Drains to Harbour inquiry. During the investigation we could see the water cycle in action as the salt water evaporated in the sun, then there was condensation when the water vapour hit the plastic. This eventually dripped into our cup as fresh water. Much more tasty (only some of us forgot to wash the rocks that acted as a weight in our cups first!). Eew!
