Take a zip lock bag and draw clouds on the outside with a sharpie then fill the bag with water and then tape it on a window that has a lot of sun and wait awhile and there should be a change in the water and that shooed what happens to water when it’s warm/sunny out
Get a tub and put a small bowl of water in it then put grass and marshmallow and close the tub and then watch it for a few days then the grass will eventually grow a little bit more and the condensation process
