Help kids see how plant grow! (Or if you're short on kids just do it for yourself - it's pretty cool!) :: Science for Kids: Observing Plant Growth with Bulbs (with a FREE printable observation sheet!) from Buggy and Buddy
Salt Volcano: Pour several inches of water into a jar. Add about of vegetable oil. Drop in food coloring and observe what happens. Shake salt on top of the oil/water/food coloring mixture. Pour or sprinkle more salt, as desired.