This is a great activity to try during a weather unit. You need 2 liter soda bottles (or another type of plastic bottle). Cut the bottle in half. Put about and inch of warm water in the bottom of the bottle. It helps to color it blue (for the ocean). Invert the top half into the bottom half (with the cap on). Fill the top with ice. After a few minutes clouds will form and droplets of "rain" will form on the inverted top. It's raining!