Rainbow in a Glass
What You'll Need
- A tall, clear glass or jar
- 4 small cups or glasses for mixing
- Honey, maple syrup, or corn syrup (the bottom, heaviest layer)
- Dish soap (middle layer)
- Water with food colouring — 2 different colours (upper layers)
- Vegetable oil (the top, lightest layer)
- A teaspoon for very slow pouring
Let's Do It!
- Start with the honey: slowly pour 2–3 tbsp into the bottom of the tall glass.
- Gently pour dish soap down the side of the glass on top of the honey — go slowly!
- Mix up two cups of water with different food colouring (red and blue work beautifully).
- Very slowly pour the red water over the back of a spoon so it floats on the soap.
- Repeat with the blue water on top of the red.
- Finally, pour vegetable oil slowly on top — it won't mix with the water!
The Simple Science
- Each liquid has a different density — how heavy it is for its size.
- Heavier liquids sink to the bottom; lighter liquids float on top.
- Honey is the heaviest, oil is the lightest — so they stay in separate layers!
- Simple language: "Some liquids are heavier and sink, some are light and float."
What They'll Learn
💡 Parent Tip
The slower you pour each layer, the better the rainbow stays separated. Use the back-of-a-spoon technique for each layer and make it a game: "Can you pour it so slowly that the colours don't mix?" After admiring the rainbow, let your toddler stir it all together and watch the colours blend — that's its own kind of beautiful!