Materials

• A drinking glass or wide-mouthed jar

• 1 cup water

• ⅓ cup of vegetable oil

• 1 tablespoon of salt (or shake for 10 seconds)

• Food coloring (optional)

Instructions

Scroll down to watch video instructions here (time 1:18).

1. Pour 1 cup of water into your glass. 

2. Pour ⅓ cup of oil into the glass on top of the water. 

3. Let the oil and water settle in the jar (and totally separate!).

Optional: Add 5 drops of food coloring before or after the oil. If you add it after the oil, you can watch how it slowly travels really differently through the oil & the water.

4. Add salt to your glass, sprinkling ½ teaspoon at a time.

5. Watch the bubbles begin to fall and rise.

6. Want more bubbles? Add a bit more salt or more water. Try stirring with a spoon and watch the liquids interact.

7. Enjoy your creation!

cool fact

How does this whole thing work?

Oil floats on water because a drop of oil is lighter, or less dense, than a drop of water. Density measures how much a certain amount of something weighs.

Things that are less dense than water will float. Things that are more dense than water will sink.

So how does the salt make bubble globs?

Salt is heavier, or more dense, than water. So when you pour salt on the oil, it sinks to the bottom of the mixture, carrying a blob of oil with it. 

In the water, the salt starts to dissolve. As it dissolves, the salt releases the oil, which floats back up to the top of the water. Cool, huh?