This is a fun experiment you can do with your kids. It just takes some water, sugar and some food coloring.
Fill a glass about 1/4 high with some water and add sugar to the water. Start with about a tablespoon and mix until the sugar dissolves. You may need to add more sugar until the water gets saturated with sugar. Once it has reached saturation, add a few drops of food coloring.
Next trickle water along the side of the glass filling it another 1/4 full. Add sugar to this next layer, being careful not to mix it will the bottom 1/4 with the food color. On this layer, mix in less sugar then the amount you added to the bottom layer. Once the sugar is dissolved add another color to the mixture.
To complete, repeat the process adding less sugar to each layer and using a different food color.
How it works. When you saturate water with sugar, it makes the solution denser. The denser solution will sink lower in the glass. The food coloring will mix with the solution in which it was added but some of the color will migrate at the junction where the different layers meet.
Hints – heating the water will help the sugar dissolve but don’t heat the water too much. I found that if I mix the next layer in a separate glass it is easier to stir in the sugar and the coloring without disturbing the lower layer.
Source: planet-science.com (Title photo)