Answer:
Materials:
4 plants
A room with lots of light
A room with no light
A room with partial light
A room with very little light
Put one plant in front of a window. Put the next plant in a dark room, like your basement cellar or under your bed. Put the third one in a room with partial light, like maybe your bedroom with one window half-closed. Put the last one in a room with little light, like maybe in your bathroom or something with the light on. Wait a few days and only give a tiny bit of water to each plant, and then after a few days go back and check on the plants. Hopefully the one that was in full light will be the biggest, the one in the partially lit room will be the next biggest, the one in the little light room will be not very big, and the one in the dark room will be the smallest. Have fun experimenting!