Never polish your tarnished silver-plated silverware again! Instead, set up a ‘silverware carwash’ where you earn a nickel for every piece you clean. (Just don’t let grandma in on your little secret!)
We’ll be using chemistry and electricity together (electrochemistry) to make a battery that reverses the chemical reaction that puts tarnish on grandma’s good silver. It’s safe, simple, and just needs a grown-up to help with the stove.
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Here’s what you need:
- stove (with adult help)
- skillet
- aluminum foil
- water
- baking soda
- salt
- real silverware (not stainless)
Download Student Worksheet & Exercises
You can safely dip it into a self-polishing solution:
- In a saucepan lined with aluminum foil, heat a solution of 1 cup water, 1 teaspoon baking soda, and 1 teaspoon salt.
- When your solution bubbles, place the tarnished silverware directly on the foil. (Try a piece that’s really tarnished to see the cleaning effects the best.)
What’s happening? This is a very simple battery, believe it or not! The foil is the negative charge, the silverware is the positive, and the water-salt-baking-soda solution is the electrolyte.
Your silver turns black because of the presence of sulfur in food. Here’s how the cleaning works: The tarnished fork (silver sulfide) combines with some of the chemicals in the water solution to break apart into sulfur (which gets deposited on the foil) and silver (which goes back onto the fork). Using electricity, you’ve just relocated the tarnish from the fork to the foil. Just rinse clean and wipe dry.
Toss the foil in the trash (or recycling) when you’re done, and the liquids go down the drain.
Exercises
- Where is the electrolyte in this experiment?
- Where does the black stuff that was originally on the silverware go?
- Where’s the electricity in this experiment?
- Where would you place your DMM probes to measure the generated voltage?
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