Friday, August 22, 2008
This week, I went to the store to purchase dry ice to put in my new buckets of food storage flour (I've been told dry ice kills any bugs or anything that may be in flour - it may be an old wives' tale but I still do it), and on a lark I bought a couple of extra pieces. I told my 5 year old on the way home from the store that we were going to do something very fun with dry ice, and since he had never seen it at work before, his interest/excitement was piqued. I asked him what would happen when I put the dry ice in water, and he said, "I don't know." Trying to make this a teaching moment, I prodded and asked him to guess what he thought might happen. He said, "Will it change colors? Will it float? Will it melt?" What great hypotheses! So I put the first piece in cold water and both boys watched it with awe. Then I showed them how blowing on it makes the steam/fog move out of the way. While blowing on it, E said, "It smells like the humidifier water." So we talked about how it is releasing carbon dioxide, like when we breathe out, and what creates the bubbles in soda pop. Then when the first piece melted, I asked them what they thought would happen if we put the next piece in hot water instead of cold (it bubbles even more and makes more steam/fog). This was a fun opportunity to use the scientific method to teach my kids about the properties of dry ice.