What Causes the ‘Rust’ in Old Coins and Why Does It Happen?

Rust is like a magical paint that old coins get when they're sad and tired from being around for a long time.

Coins are usually made of metal, like copper or iron. When these metals meet water and air, something special happens, it's like a tiny party where the metal starts to change color. This is called rust.

• Water helps the rust party start.
• Air gives the party oxygen, which is needed for the magic.
• Time lets the party go on and on, making the coin look older and more magical.

If you leave a coin in a wet place, like under a leaky faucet, it will get rusty faster. It's as if the coin is saying, "I'm getting old!" with every little spot of rust that appears.

Sometimes coins even get a greenish tint, that’s another kind of magic, but that’s a story for another day!