Create a Sugar Rainbow

Materials

• 6 clear glasses

• 6 straws

• Food coloring (we like this set)

• Sugar

Directions

1. Fill each of the six glasses with water. Note: The glasses need to be stable and about as deep as the straw is long.

2. Add one color of food coloring to each glass. Stir.

3. Leave the first glasses as it is (just colored water)

4. Add 1 tsp sugar to the second glass

5. Add 2 tsps sugar to the third glass

6. Add 3 tsps sugar to the fourth glass

7. Add 4 tsps sugar to the fifth glass

8. Add 5 tsps sugar to the sixth glass

9. Stir the solution in each glass until the sugar is completely dissolved.

10.  Hold the straw near one end, wrapping four fingers around the straw and placing your thumb over the straw’s top opening. To make your Sugar Rainbow, lift your thumb off the opening, dunk the lower end of the straw about 1” (3 cm) into the plain water. Cap the straw firmly with your thumb, lift it out of the water, and dip it quickly into the 1 tsp solution. This time, go a little deeper than you did into the first glass. You want the layers to be about the same thickness.

11. With the straw in the liquid, lift your thumb but quickly replace it. Lift the straw and you’ll have the first and second colored solutions in a stack inside the straw. Continue the dipping process until you have all six colored solutions inside the straw.

What’s Happening?
Density is the measurement of how much “stuff” is packed into a measured space. Nearly every substance and material imaginable has a different density. This is especially true for the six solutions you made using sugar and water.
By increasing the amount of sugar in the solution but keeping the amount of water constant, you create solutions that have increasing densities. The more sugar that’s mixed into a measured amount of water, the higher the density of the mixture. As the Sugar Rainbow reveals, a solution with a low density stacks on top of a mixture with a high density.

adapted from Steve Spangler Science