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Fall is upon us, and with it comes corn! Corn on the cob, creamed corn, cornbread, tamales (can’t make one without a corn husk), and, of course, popcorn. Now, I know you can eat popcorn at any time of the year. Heck, you can eat regular corn at any time of the year. But it just wouldn’t be a proper autumn without some corn, so in today’s experiment, we’re going to turn some popcorn into … "hop" corn.
Sorry for the corny joke! Our experiment today involves an old favorite on Saturday Science: baking soda and vinegar!
Materials:
- A large, clear glass
- Unpopped popcorn kernels
- Baking Soda
- White vinegar
- Water
- A spoon
Process:
- Fill your glass about 3/4ths full with water, and use your spoon to stir in some baking soda.
- Put a spoonful of popcorn kernels into the baking soda and water mixture, not quite enough to cover the bottom of the glass.
- Top off the water with some white vinegar.
- Begin to observe what’s happening. What do you see in the glass? What is happening to the popcorn?
- Experiment with the amounts of baking soda, water, and vinegar. Can you create different effects by changing them up?
Summary
As you may remember from previous Saturday Sciences, when baking soda and vinegar is mixed a chemical reaction occurs. One of the products of this reaction is the gas carbon dioxide (CO2). It’s what fizzes up when you mix dry baking soda with vinegar. In this case, we’ve added water to the mix, which means that the carbon dioxide has to bubble through the water on its way out into the air. Some of the bubbles attach themselves to the popcorn kernels. Since the bubbles are less dense than the water, they float, and if enough bubbles attach to a kernel of popcorn, they make the popcorn float, too! Eventually, though, the bubbles break off or reach the surface and join the air, which makes the kernel float back down to the bottom. Since there’s still more gas being produced, though, kernels keep hopping up and back down again until the reaction has finished.
Carbon dioxide is also the gas that’s used in carbonated drinks like soda. Another experiment you can try is to drop some popcorn kernels into a mostly full bottle of pop, put the lid on, and give it a couple of good shakes. What happens to the popcorn in that situation?
Want more Saturday Science? See all of our at-home activities on the blog or Pinterest.
