This week in Science & More we looked at Carbon Dioxide three different ways - we created it, we watched it, and we changed it.
I asked the kids what they knew about carbon dioxide, and they told me that you exhale it. Someone added that trees inhale carbon dioxide.
And so we started with creating carbon dioxide. I had prefilled a balloon with 1 teaspoon of baking soda and added 2 teaspoons of vinegar to an empty 8oz plastic water bottle. I asked everyone what they thought would happen when we put the balloon over the bottle and they were all very sure that it would get blown up. They were really hoping it would inflate enough to pop, but I had made sure to avoid that by not putting too much baking soda and vinegar in such a small bottle. Of course, just as they predicted, when the baking soda and vinegar mixed, they created a chemical reaction that caused the balloon to inflate!
I showed them a diagram of vinegar (acetic acid) and baking soda (sodium bicarbonate) and used Chinese Checkers pieces to model what had happened in the water bottle.
(image found on https://sites.google.com/site/baumannchemistry/unit-8-stoichiometry)
Next, we watched carbon dioxide in action. I asked them if they knew another name for soda. They weren't sure, so I gave them a hint. I told them it had to do with the bubbles in soda. They still weren't sure, so I explained the word carbonated. We filled a cup with ginger ale and added a handful of raisins. We watched as the bubbles of carbon dioxide got stuck on the raisins and carried the raisins to the surface, making it look like the raisins were dancing. I asked why they thought the bubbles were able to carry the raisins, and they guessed that it was because the bubbles were made of a gas that was trying to escape the soda. I asked if they thought that meant carbon dioxide was heavier or lighter than the soda, and they all agreed it meant it was lighter.
Our final experiment was to change carbon dioxide, and it built a bit on the previous Science & More session about acids and bases.