- Education and Science
Lava in a Cup Experiment
- Clear Glass
- 1/4 Veg. or Canola Oil
- 1tsp+ Salt
- 4-5 Drops Food Coloring
- Fill the clear glass about 3/4 full of water.
- Add to the water, 4-5 drops of your favorite color of food coloring.
- Pour in the oil.
- Sprinkle the salt on top. More and more salt can be added for the continuation of the experiment.
So what is causing this interesting mysterious lava to occur? First off we have to explore the world of densities.
Oil is less dense then water, thus it floats to the top of the glass and "sits" on the more dense water.
Why salt? The salt is heavier than the oil, so it sinks to the bottom and takes some of the oil with it. Once this salt mixes with the liquid, it dissolves and back up the oil goes as the salt stays at the bottom.