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.
Weather experiment - take a clear plastic cup and add plain water. Put a small amount of shaving creme on top. Then a few drops of red and yellow food coloring. The food coloring slowly finds it's way down into the water to make ORANGE rain! What fun!
These work great! Did them for a school science night using smaller bottles. They look like lava lamps. - Fireworks in a bottle - looks fun and easy! bottle of water, oil, coloring (food coloring, paint), alka seltzer.