1. Fill the plastic bottle half full with oil.
2. Add ten drops of food colouring to 2 cup of water.
3. Pour the coloured water into the bottle until it is full.
4. Watch as the oil rises above the water
5. Once the liquids have settled, add two 1/4 pieces of an Alka-Seltzer tablet to the bottle.
6. Once all of the bubbling has stopped, tightly screw on the bottle's cap.
7. Options:
Add more tablets once the bubbling has finished
Add glitter to the bottle for additional sparkle!