Colorful sugar water density tower – the lab
Fill your cups with 1 cup of warm water and add food coloring to the water. You want a different color for each density. We used blue, green, yellow and red.
Add 2 tablespoons of sugar to the 1st cup, 4 tablespoons to the 2nd cup, 6 tablespoons to the 3rd cup and 8 tablespoons to the last cup. Our colors were:
Stir the water until the sugar is dissolved. It is crutial that all of the sugar is dissolved in each cup. You may need to supersaturate the sugar water solution to get all of the sugar to dissolve. Place the cup in the microwave for 20-30 seconds to warm the water and dissolve more sugar. Continue stirring until all of the sugar is gone.
Start with the cup with the most sugar. Using a pipette, dropper or back of a spoon, begin adding the first layer of sugar water.
After the first layer, things get challenging. Carefully drip the next dense layer onto the surface of the first. The best technique is to place the pipette right above the surface of the first layer and against the glass. Slowly drip the next color onto the first. This will take a lot of patience. Go slow.
The colors will begin to mix at first and then your original color will start to show.
Repeat with the next dense color and the least dense color until you have stacked all of the colors.
As you add sugar to the water, more and more sugar molecules will take over the space, making the water more dense. The cup containing the 8 tablespoons of sugar will be the most dense, the cup with 2 tablespoons will be least dense.
With this sugar water experiment, we put the most dense solution on the bottom. Why do you think that is? What will happen if you try it with the least dense solution on the bottom?
If you attempt to dissolve sugar in water, you reach a point where you cannot dissolve any more sugar. This is called a saturated solution. However, if you heat this solution, more sugar will dissolve. When the solution is cooled, the sugar will remain in solution. This is called a supersaturated solution, which is very unstable and will crystallize easily.
Density Column Mixup
What happens if you shake or mix up your sugar density column? The colors will not separate and go back to the rainbow, like a water-oil density tower. The sugar will mix evenly with the water.
Try different mixtures like water and baking soda, water and salt, oil and sugar and see if you can build density towers like the sugar water tower.
Thanks to Liz Heinecke at the Kitchen Pantry Scientist for this twist on our 9-Layer Density Column.
This experiment takes a lot of patience. You won't see the color you are adding right away. Keep carefully dripping the sugar water solution and you will see it begin to stack up.