Here’s what you will need:
- a clear plastic or glass bottle with a lid or cork
- vegetable or mineral oil
- food coloring
- a flashlight
- an effervescent lozenge (aka Alka Seltzer or Airborne)
Here’s what you will do:
1) Fill your bottle ~ 3/4 with oil, then add water, being sure to leave a little room at the top. Because water is more dense than the oil, it will sink to the bottom, and will form some neat little bubbles.
2) Next, add several drops of your favorite color of food coloring into the bottle. This will also sink to the bottom. While the color mixes in, break your seltzer tab into several small pieces.
3) Be sure you have your flashlight now! Turn on the flashlight and lower the lights or turn them off! One at a time drop in your lozenge pieces
4) Enjoy the action! Put on the lid or cork to store once the bubbling stops.
5) Anytime you want a little lava lamp action, just flip it upside down and enjoy. (Whatever you do, don’t be tempted to heat up, plug in, or otherwise agitate your homemade lava lamp.)
Source: USA Science Festival and About.com