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Sugar Water Density Experiment

What happens when you combine blue, green, yellow and red water in a single glass? Brown, right? Not necessarily! By dissolving different amounts of sugar in each glass of water, you change the densities, allowing the colors to stack like a rainbow! For this sugar water density experiment, you’ll need a few common household items, listed below.

Sugar Water Density Experiment Step 1


5 glasses

warm water



food coloring


Sugar Water Density Experiment Step 2


1. Fill four glasses with 1/4 cup of warm water each.

2. Add 1 tbsp of sugar and 2 drops of red food color to the first glass. Add 2 tbsps of sugar and 2 drops of yellow food color to the second glass. Add 3 tbsps of sugar and 2 drops of green food color to the third glass. Add 4 tbsps of sugar and 2 drops of blue food color to the fourth glass. Stir to dissolve the sugar.

Sugar Water Density Experiment Step 3

3. Use the syringe to transfer about half of the blue water into the empty glass. This is where you’ll make your rainbow.

4. Still using the syringe, transfer half the green water into the rainbow glass. Add it slowly on top of the blue water. It will sit on top. Add the yellow next.

5. Finally, add the red on top of the yellow. You’ll see a beautiful rainbow!

Sugar Water Density Experiment Final Result

What’s happening?

Each glass of colored sugar water has a different density. Density measures how much mass is in a given volume. In other words, it measures how tightly stuff is packed together. The blue water has four times as much sugar dissolved in it than the red water, which means that it is four times denser. Because it has a great density, the blue water wants to sink to the bottom. The less dense red water stays on top of the denser liquids.

Take it further:

Slowly drip the blue water on top of the rainbow. What do you think will happen when the densest liquid is put on top of liquids that are less dense? What actually happens?

Fill the syringe with more yellow sugar water. Add it to the rainbow by plunging the full syringe down until the tip is in the yellow layer and then release it slowly. What happens?

Put the empty syringe into the completed rainbow and see if you can remove one color and return it to its original glass. What happens?

Gently stir the rainbow one time. What happens? Now stir vigorously. Did you get a different result?


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