Dancing Grapes
An experiment about buoyancy.
— June 10, 2024
How do you explain buoyancy to a preschooler? You do not. Instead you show and let them engage with a science experiment, specifically this one!
My boys love making grapes dance. My now five year old has completed the experiment several times because he loves it! He explains in detail each step of the process and why it works.
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Also, this experiment is a part of a week’s worth of lessons that use grapes. Be sure to check out Gg is for Grape at the button below.
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Dancing Grapes Experiment
Set up
Give your child a coloring page, available at Gg is for Grape. Have them color the page while you gather the supplies. There are not many supplies but it’s nice to keep them distracted.
I gather the grapes, cans of sparkling water, and 2 two wide mouth mason jars. I prefer to do this experiment at the island in our kitchen. They are able to all engage with the experiment without fighting for space.
The second part of the experiment is very messy and you may want a cookie tray and/or towels underneath. If you plan to do the second part then you will need white vinegar and baking soda. But I set these in another area of the kitchen until we are ready to use them. Of course, you can decide not to do this part as well.
Gather round
After everything is out, I invite the kiddos to gather round the island with their step stools. I direct their attention to a jar and let them watch me fill it up with water from the tap. Then I open the sparkling water cans and allow the kids to take turns pouring them into the other jar. Almost three cans will fit in a large, wide mouth mason jar. Do not fill completely because when you add the grapes later the water level will rise.
Before we begin including grapes we discuss the difference between the two glasses. Depending on the age of your child will determine how technical the explanations are.
I’m working with three kiddos ranging in ages from 2- 5. I first ask questions.
Questions to ask before beginning.
- What is different between the water in the two glasses?
- Do you know what those bubbles are called? -carbon dioxide bubbles.
- What will happen to the grapes in each glass?
Add the grapes!
After they have hypothesized it is time to add grapes. I recommend beginning with the tap water jar because it will hype up the excitement level.
Next, allow your child to drop in a few grapes to the sparkling water and simply allow them to observe. My boys enjoy poking them down as they float to the surface.
The only monitoring I have to do is to make sure that they are sharing and not overloading the jar with grapes.
We did have an accident where Mo, 2 year old, was poking at the grapes and his step stool slipped. He grabbed the jar as he dropped about a foot to the ground. He received a face full of water from the jar being pulled towards him. Oops! He was completely fine and since I had towels at the ready the mess was easy to clean up. There were tears from being surprised, and now wet, but he quickly recovered. Lesson learned, have towels at the ready.
Optional second step.
This one gets messy. We are going to create our own carbon dioxide bubbles using white vinegar and baking soda.
Yes, it will get messy so have towels handy and place a cookie sheet under the jar.
Pour out half the water from the tap water jar and replace it with vinegar. There should be a 1:1 ratio of water to vinegar. You can place the grapes in it now or after. Place a few teaspoons of baking soda in and mix quickly. It will “foam” over and a lot will leave the jar. However, you should see the grapes rise to the top.
Disclaimer
The second step here is messy and not always reliable. I’ve skipped this part of the experiment in the past just to avoid the hassle. Other times we do it because I want to show the boys that it does not have to be store bought, in cans. Carbon dioxide bubbles are a natural chemical reaction from common household items.
Continuous learning
Your child will think about this experiment for days and weeks to come. It was a few weeks after having completed this science experiment and Mick asked for sparkling water, which my husband and I usually drink at dinner. Daddy poured a small half glass for Mick. We then realized he was not drinking it, but was watching rice, from our dinner, dance. A strawberry was next on the docket but it did not dance.
Daddy and Mick then discussed the bubbles not being able to carry the denser food the top. Encourage your child to experiment with other foods to see what is light enough that the bubbles are enough to make it buoyant. Share your discoveries in the comments! Or share your thoughts over on Instagram at Playing for Hours. I’m better able to connect over there!
If you enjoyed this Dancing Grapes science experiment and are seeking more letter “G” or grape activities you’ll find it at Gg is for Grape.
All the letters of the alphabet are themed and have an exciting week’s worth of lessons for your 3-5 year old. Find it all at Playing for Hours’ Letter of the Week. Click the button below to access it all for free.
Dancing Grapes Experiment
Activity Instructions
Materials needed
1 can of Seltzer water
Two, tall, clear glasses
Tap water
Baking soda
White vinegar
Cookie tray – for easy clean up
Towels
*Safety glasses
*Gloves
Instructions
1) Now is the time to put on all our safety gear, if using. Even though we are creating a completely safe experiment and chemical reaction, having your child don glasses and gloves can make them feel like professional scientists.
2) With your child fill up one glass of water from the faucet (leave enough room for an equal amount of vinegar to be added – 1:1, water: vinegar). Then, fill up the second glass with seltzer water. Place these glasses on the cookie tray.
3) Now drop a few grapes in each glass and wait. At the beginning the grapes are too dense to float. Explain this to your child.
4) Soon, enough of the carbon dioxide bubbles in the seltzer water will gather around a grape so that it will become buoyant and rise to the surface. Be sure to explain how they’re helping the grape to become buoyant.
5) After the grape reaches the top the bubbles burst and the grape will fall. This will continue with all the grapes and until the seltzer goes flat.
6) During this time, be sure to bring your child’s attention to the tap water glass and how it’s doing nothing because the seltzer water is carbonated and the tap water is not.
7) Pour in the same amount of vinegar as there is water into the tap water glass. Stir.
8) Now allow your child to stir in a few tablespoons of baking soda. It will overflow depending on how full the glass is. Having the cookie sheet underneath or a towel ready is advised. Once the bubbling slows stop stirring and allow the grapes to dance. It’s not nearly as strong or lasts as long as the seltzer water but the kiddos will enjoy being the influence behind making them dance.
9) If your child wants to try other small fruits or berries, let them! If they want to try more or less baking soda and vinegar, let them! Now is the time to let them experiment with the safe chemical reaction that is occurring.
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