DIY Lava Lamp
Introduce kids to a flash from the past with DIY lava lamps. Save some water bottles for repeat experiments.
Materials
Empty water bottle
Vegetable oil
Water
Food coloring
Alka-Seltzer tablet
Directions
Fill the empty water bottle about 2/3 full with vegetable oil
Fill the rest with water, leaving a little of space at the top
Notice that the water sinks below the vegetable oil. Oil and water do not mix. Oil floats on the surface because the water is heavier (has a higher density)
Add the food coloring
The food coloring will only mix with the water, not the oil
Stir with a chopstick or knife (don’t shake the bottle)
Break an Alka-seltzer tablet into four pieces. Drop one piece into the bottle at a time
Why Does It Work?
When you drop in the Alka-Seltzer, it sinks to the bottom and starts dissolving. As it dissolves, it forms a gas that rises to the top and takes a little of the colored water with it. The gas bubble breaks on the surface and the colored water sinks back to the bottom.
adapted from NoGuiltMom.com