Making lava lamps

We made lava lamps in summer school today. So cool and so easy!

1. Fill an 8 oz. water bottle about 3/4th full with vegetable oil.

2. Add water but leave a little room at the top.

3. Add 5-10 drops of food coloring.

4. Drop small  pieces of Alka-Seltzer tablets in.

5. When the bubbling stops, put on the cap.

6. Tip the bottle and watch the reactions!