Dear parents,
We were going to make bouncy balls today but after attempting to do the experiment at home, I realized it was much
more finicky than I first anticipated and I was concerned the kids would come away more frustrated than anything else.
An experiment that’s no fun is…well…no fun so, today, instead of bouncy balls we talked about multi-step chemical
reactions by playing with vinegar and baking soda.
What is a multi-step reaction? It’s a reaction that looks like one step but is really two or more reactions in quick
succession. The baking soda and vinegar reaction is a two-step reaction:
1. The vinegar (the acetic acid in it) reacts with the baking soda (sodium bicarbonate) to create carbonic acid.
2. Carbonic acid is very unstable so immediately begins to decompose into carbon dioxide and water. The bubbles
are just the carbon dioxide escaping from the solution that’s left behind.
What’s left over is a very diluted solution of sodium acetate in water.
CH3COOH + NaHCO3 –> CH3COONa + H2CO3
H2CO3 –> H2O + CO2
Dinner table talk:
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One of the experiments we did allowed the kids to see that the bubbles (holding carbon dioxide) were heavier
than the air. That’s why the bubbles spill over the top of the cups like water overflowing.
The other experiment we did allowed us to see if we could mix colors with baking soda and vinegar of if the
bubbles get in the way.
You can try these experiments at home with some variations:
o Use warm vinegar instead of cold.
o Baking soda and lemon juice also produces carbon dioxide and will also bubble but, it’s also an
exothermic reaction so it will create some heat. Compare this to the baking soda and vinegar reaction. Is
that one exothermic as well?
Science Delights © 2013
www.sciencedelights.com
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