Materials
- Student Handout (pdf)
- Food Coloring – Red, Blue, Yellow, & Green
- Erlenmeyer flask filled with warm tap water
- Graduated cylinder
- 4 Stirrers/Sticks
- 4 Pipettes
- 1 Spoon
- Granulated Sugar
- 3 Test Tubes
- Test Tube Rack
- 4 Clear Cups
This sugar density activity is one I have never tried before, I actually ‘borrowed’ the idea from my son’s HS Chemistry Teacher. He came home and told me they made different colored layers using only sugar, food coloring, and water. I immediately jumped on the computer and thought about how to use this in my 6th grade classes, we are in the middle of our density unit and it would be a perfect opportunity to try it out.

One of my goals for this year is re-examine my lessons and see which activities I can make more open-ended when appropriate. For this activity, most of the resources I found told the students exactly how much sugar to put in each layer and what order to place the colors into the test tube or some other type of container. I didn’t want my students to follow step by step procedures, but wanted it to be more of an exploration type of activity. I had no idea how this would turn out but gave it shot anyway.
I gave them the problem, the parameters, the tools to complete the activity, and sent them on their way. It was great to see them figure out how to solve the problem, talk out strategies, and to see them go through the trial and error process. Each group came up with a different way to solve the problem and some groups struggled more than others. I met with each group to facilitate, ask questions, and had them explain to me what they were doing and why. Overall, it was a successful lesson, they enjoyed the activity, and it really solidified their understanding of density.
I am also incorporating more open ended writing in science and I enjoyed reading their reflections about the activity.
Do you think this would work with salt instead of sugar? Thanks! Love your site and all your resources
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Yes, salt works very well but sugar is less expensive if you need large quantities
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Not sure if you still check comments, but do you know if this can be done with salt rather than sugar? Thanks! Love your site
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Hi, I really enjoy your blog it saves me millions of time especially at a school with no curriculum. I love this rainbow density lab with sugar. Just a couple questions: How much in total water do the students need in their flask to complete the whole lab? I see it says they need 60mL in each cup, but between each trial do they dump out the made solution and then start all over?
Thank you for your help,
Sharyl
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For the rainbow density lab, the students can add more water to their cups to keep it around 60 mL and then add additional sugar. Have a great school year! ~Liz
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