Frustrated over a Simple 4th Grade Experiment

Hello, I was wondering if you could assist me with a question. I have been desperately trying to help my 4th grader with a simple experiment we found in a book for children. It simply says to put a copper strip into salty water along with a chromium key and attach both to a 4.5V battery. When cannot get anything to happen. Can you tell me what I may be doing wrong? The first thing that I am thinking may be wrong is that I really don't know where to find a pure chromium key. We went to Wal-mart and got a key and I am sure that it is some sort of alloy. Please help me get the tears out of my little one's eyes ! THANKS ! Joshua P. (4th Grader) and Mom (Monica P.)

Please name the book, Monica, because this reference is a bit crazy. First, keys are never made of chromium, although they might have a thin plating of nickel and possibly chromium. But secondly, you won't be able to plate the copper onto the chromium, nor the chromium onto the copper. Thirdly, 4.5 volts is way too much. Fourthly, the experiment will be far more practical if you use vinegar ⇦in bulk on eBay or Amazon [affil link] with a little salt in it rather than salt water.

Plate the copper onto a quarter rather than onto a key and your son will be happy. Please see our FAQ: "Plating - How It Works" to see how to plate copper onto the coin. Good luck.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

Ted,
Correct that the keys are not chromium. Actually they are generally brass with a nickel plate, no chromium.