How to make a rainbow in a glass at home
You don’t need any chemicals for this experiment – you can do it right now!
Perform this experiment only under adult supervision.
Reagents and equipment
- sugar (refined sugar works best);
- 500 mL boiling water;
- 6 glasses;
- food coloring (4-5 different colors).
Distribute 500 mL boiling water evenly among 5 glasses. Don’t add any sugar to one of the glasses. Add to the rest of the glasses in turn: 2.5, 5, 7.5, and 10 sugar cubes. Add different colors of food coloring to each glass. Stir each solution thoroughly and let cool. Use separate pipettes to transfer each solution into another, single glass. Pour the solutions gently down the wall of the glass. Start with the solution with the most sugar (10 pieces) and continue in decreasing order. Voila, you’ve made a sugar rainbow! If the solutions mix too easily, try refrigerating them or increasing the difference in their sugar concentrations.
Density is the ratio of a body’s weight to the volume it occupies. If different masses of sugar are dissolved in two equal volumes of water, then the solution with more dissolved sugar will be denser. Moreover, if you arrange the solutions in order of decreasing density from the bottom up, they won't mix right away since no currents will form that could lead to the mixing of the solutions. It’s worth clarifying that diffusion between the layers does occur, so the sugar and dye molecules from the more concentrated (denser) solutions gradually diffuse into the less concentrated solutions, slowly equalizing their concentration throughout the volume of the vessel.