Copper Coating

Many metal objects around you are plated - they have only a thin coating of the metal you see covering another metal (usually less expensive). In particular, a lot of things are gold-plated or silver-plated. Gold and silver cost too much to experiment with, but here's an easy way to copper-plate a nail.

What you'll need:
1/4 cup (50 mL) of lemon juice or vinegar
Plastic or paper cup
10 to 20 dull pennies
Salt
2 small iron nails (not the galanized kind)
Steel wool scouring pad

Pour the lemon juice into the cup and drop the pennies in. Add a pinch of salt. What do you see happening? Wait three minutes. While you're waiting, scrub one of the nails with the scouring pad to clean off the surface. Rinse the nail well. Just put the second nail off to the side. Drop the cleaned nail into the cup, and wait about an hour. After that time has passed, take the nail out and compare it to the one you set aside. What do you see? When you're done, make sure to pour the lemon juice or vinegar down the drain and to throw the cup away.

As you may know, pennies are coated with the element copper (Cu). When you dropped them into the lemon juice or vinegar, bubbles formed. Metals like copper often react with acids (like the citric acid in lemons or the acetic acid in vinegar) to form bubbles of hydrogen (another element!) gas. You may have noticed that this solution changed color as some of the copper dissolved. When you added the iron (yes, yet another element!) nail, the dissolved copper collected on its surface, giving the nail a brown coat of copper.

The instructions said that you should not use a galvanized nail (which is coated with zinc - these elements are everywhere!), but you might want to try one, just to see what happens!