Divide a large fish tank into two sections with a piece of plastic cut to fit inside the tank. Place the divider at about 1/3 of the way from the end of the tank, and seal the edges with silicone. Put soil in the bigger section so that it slopes up away from the divider and plant small vegetation in it. Fill the other section with water but don’t over fill it. Then place a glass lid on top of the tank. Give it a few days and your water cycle will start working and the process will be visible.