First Class tested which liquid would clean dirt of a copper coin the best.
They chose honey, CocaCola, ketchup, soapy water and water as the liquids to test. (Teacher was, of course, thrilled at the thought of cleaning honey off of our equipment.)
First they made predictions about which would be most effective. CocaCola and Soapy water were the most popular guesses.
Second each group chose five coins and covered them in the liquids for 20 minutes. To make sure we had a fair test, every group chose five coins that were equally dirty.
Finally the boys rinsed the coins and ranked them in order of cleanest. Unexpectedly, the ketchup lifted the most dirt off of the coins.
Well done to all of the boys for such good participation and discussion.