Density Rainbow Jar Science Experiment
Layer colored liquids of different densities in a jar to create a rainbow. Honey, dish soap, water, and oil stack perfectly — and your child discovers why.
What You'll Need
- 1Tall clear glass or jar
- 2Honey
- 3Dish soap
- 4Water with food coloring
- 5Vegetable oil
What You'll Need
A tall, clear glass or jar
Honey
Dish soap (colored variety works best)
Water with food coloring
Vegetable oil
How to Play
Add food coloring to a cup of water for contrast.
Slowly pour honey into the bottom of the glass — about an inch.
Tilt the glass and gently pour dish soap down the side. It layers on top.
Very slowly pour colored water down the side. It floats on the soap.
Pour vegetable oil last. It floats above everything.
"Four layers! Heavy liquids sink, light ones float. That's DENSITY."
Try dropping small objects in: a grape, a cork, a coin. Where do they settle?
The Science Behind It
Density is how much mass is packed into a given volume. Honey is very dense — its molecules are packed tightly — so it sinks to the bottom. Oil is the least dense, so it floats. Each liquid finds its level based on how heavy it is compared to the others. When you drop objects in, they sink until they reach a liquid that's denser than they are.
Tips
Pour SLOWLY down the side of the glass. Pouring directly into the center mixes the layers.
A tall, narrow container works better than a wide one — the layers are more visible.
Drop in small objects to test their density: a grape sinks through oil and water but floats on honey. A coin sinks to the bottom. A cork stays on top.
Ask: "If we stirred this up, would the layers come back?" (Yes, with time!) Test it.
Try adding rubbing alcohol (with adult supervision) as a fifth layer — it floats on the oil.
Age Adaptation Tips
School-age kids can take more ownership. Let them lead the activity, experiment with variations, and explain what they learned.
Frequently Asked Questions
How long does this activity take?
This activity takes about 20 min, with 5 min of preparation time beforehand.
What materials do I need?
You'll need: tall clear glass or jar, honey, dish soap, water with food coloring, vegetable oil.
What age is this activity for?
This activity is designed for 5-8 years. You can adapt it for younger or older children by adjusting the complexity.
Can this be done indoors?
This activity is designed for indoor play, making it perfect for rainy days or when you're staying inside.
How difficult is this activity?
This activity has a moderate difficulty level. It may require some preparation or guidance, but is manageable for most families.
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