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Floating Popcorn Kernels - Science Project


January 26, 2012

Demonstrate buoyancy and chemical reactions

By: Kim McNeill ~ MK Publisher Southbury-Waterbury, CT
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Show your kids some science with items you probably have right now. 

 

What you need:

  • A clear, tall container
  • 3 cups of water--You can see in the video that I did not measure anything
  • 1/4 to 1/3 cup of baking soda
  • 1/8 cup of unpopped popcorn kernels
  • 1/4 to 1/2 cup of white vinegar

 

 

What you do:

  1. Mix baking soda and water in the clear container
  2. Add corn kernels
  3. Pour in vinegar--do this part in or near the sink. I'm surprised mine didn't overflow with foam
Adjust the amounts for whatever size jar/cup/vase you are using. 

See a video of our results:

 

 

 

Do this for all ages from preschool up through tween. The youngest kids will notice the motion. Make sure they look at the kernels and see that they have bubbles on them. 

 

For the next age of kids, you can explain about bubbles being pushed up by the water (floating) and the corn kernel being pulled down by gravity. Then explain that when the "bouyant" force of the bubbles is stronger than gravity, the kernel rises. The kernel falls after lots of the bubbles break when they rise to the surface.

 

The oldest kids can do all of that and perhaps try to figure out how there is gas to make the bubbles. To figure it out, they could even do a science experiment by following the steps below.

 

Try popcorn kernels in plain water.

Try kernel in a mixture of water and baking soda.

Now put some kernels in water with vinegar

None of those will show a lot of bubbles on the kernels.

Now put the kernels in seltzer water.

Seltzer water has bubbles because it is carbonated. A chemical reaction occurs when baking soda and vinegar are put together; they create carbon dioxide, the same gas dissolved in seltzer water. 

 

Kim McNeill is the editor and publisher of Macaroni Kid for lower Litchfield County/upper New Haven County CT, blogger at Hearst CT Media Group, Kim's Play Place, and freelance writer for CBS Local in Connecticut. 


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