The second of the “Science in the Kitchen” activities involved salsa and pennies. Camp counselors gave each child a penny and a spoon and instructed them to cover one side of the penny with the salsa. They then were told to drop the penny into the pitcher of water at the center of the table. After a few minutes the pennies were then retrieved. Upon inspection, the majority of the pennies now had one shinier side and one side that remained dull. Some pennies were now very shiny and some only slightly more than before.
Our table had some wonderful counselors who were a bit over eager to under-explain (new word) what actually happened. They wanted to connect the dots for the kids so badly that a significant learning opportunity was missed.
One of the best things we can do as we teach our children, once a phenomenon has been observed, is to ask “Why?” Instead of asking why, the counselors rushed to explain what had happened.
The next step for the teacher is to wait, at least 5 seconds or longer if necessary, and then ask some more prompting questions if the children don’t take the bait. Then sit back and wait for the theories to fly at you. If you’re in the mood, catalog them on your dry erase board and if you have the time prompt your children to test them by switching your line of questioning from “why” to “how can we find out if we’re right?”
Assumptions
Now here is where I went wrong. After prompting some discussion about physical vs. chemical reactions, I assumed the citric acid in the tomatoes was the work horse of the experiment. You know what happens when you assume?
Follow these two link to see who is really responsible for cleaning the crud (copper oxide) off of the penny and for a clever test that demonstrates the scientific process at work in this activity. After reading through one or both of these posts you will be more than ready for a Salsa and Penny snack time! Don’t forget the chips.
http://www.cruftbox.com/cruft/docs/cleaningcopper.html
http://oneshetwoshe.com/2011/03/an-easy-penny-science-experiment-interesting-facts.html
