What Will Make a Penny Rust?

A. Hello Peggy.

No gasoline! 11-year-olds should not be using gasoline in such experiments! She could try 3-in-1 oil or sewing machine oil or motor oil as a petroleum-based entry in her corrosion tests.

And I'd also advise against mixing other ingredients into household cleaners; while I don't think that salt is dangerous to add to ammonia, in principal it's dangerous to add things to ammonia or bleach, or to household cleaners containing either.

She could try beer, milk, rubbing alcohol, vinegar, lemon juice, vegetable oil, antifreeze, or shampoo for some additional ideas. If you can bend, saw, or cut the pennies so the silvery colored zinc core is exposed, they'll corrode quicker.

But actually, nothing can make a penny actually "rust" because rust is "iron oxide", so only things with iron in them can "rust", whereas a penny is made of copper plated onto a zinc core). But anything acidic or salty will cause the pennies to discolor or corrode! Good luck.

A. Hi Kristy. All of those things can be tested to see if they make a penny corrode. Even water will, but some will work faster.

But note that "rust" is iron oxide, a reaction between iron and oxygen. If you don't have iron, you can't make real "rust" -- and pennies have no iron in them. But the copper coating can turn brown or green, and if you cut the penny into pie slices, the zinc core can turn white. Good luck!

Regards,

A. Be nice.
Sprite can do the job.