🍭 Density Rainbow
Layer four coloured sugar-water solutions of different densities to create a stunning rainbow that doesn't mix!
🧰 What you need
🔬 Steps
- 1
In cup 1: mix ½ cup water + 4 tbsp sugar + purple/violet colour. In cup 2: ½ cup water + 3 tbsp sugar + blue. Cup 3: + 2 tbsp sugar + green. Cup 4: + 1 tbsp sugar + red/yellow.
- 2
Stir each solution until the sugar is fully dissolved.
- 3
Carefully pour the purple solution (most sugar) into the tall glass.
- 4
Using a spoon held against the inside glass wall, slowly pour the blue solution down the spoon — go very slowly!
💡 Slow is the key — if you pour too fast the layers will mix. Let the liquid slide gently down. - 5
Repeat for green, then red — always pouring down the spoon very slowly. Admire your rainbow!
💡 You can use a dropper or syringe for even more precision.
🧠 The Science
Density is how much mass is packed into a volume. Adding more sugar to water makes it denser (heavier for the same volume). The purple solution has the most sugar — it's the densest — so it sinks to the bottom. The red solution has the least sugar, so it floats on top. When you pour each layer very slowly, the denser liquid stays below the lighter one. This is the same reason oil floats on water and the ocean has layers of different water temperatures!
📚 Related Lessons
- 🌊 Water Around Us — Water covers most of Earth — in oceans, rivers, lakes, rain, and underground wells!
- 🔄 Water Cycle — Water evaporates from oceans, rises as vapour, forms clouds through condensation, and falls as rain — endlessly!
- 🚰 Safe Water — Not all water is safe — germs, chemicals, and sewage contaminate water, but boiling, filtering, and chlorination make it safe!