How to Make Your Own Lava Lamp

Create a mesmerizing, bubbling lava lamp using simple kitchen ingredients and the science of density. HowTo: Family Edition: family how-tos that actually help.

1. Fill the bottle. Fill your bottle about one-quarter full with water. Ask a grown-up to help you pour the vegetable oil into the bottle until it is almost full, leaving about an inch of space at the top. Wait a few minutes for the oil and water to separate completely.
2. Add some color. Add about 10 drops of food coloring to the bottle. Watch as the droplets sink through the oil and mix only with the water layer at the bottom.
3. Start the reaction. Break one effervescent antacid tablet into four pieces. Drop one piece into the bottle and watch the bubbles start to move. When the bubbling stops, you can add another piece to keep the show going.