Clean the Coin

Clean the Coin

Grace Kim - 4th Grade / Gabrielle Ferrari King

Project Summary

Question - How do you clean copper?
Hypothesis - I didn’t think any of my liquids would clean well.
I will put 5 dirty pennies into 5 different liquids. After waiting, I’ll take out the pennies and see which one is cleanest. I used Oil, water, vinegar and salt, soy sauce, and ketchup. When I took them out, Ketchup was the best cleaner!
Watch the video here!

Spoiler - read this only after you watch the video!

The ketchup was the best cleaner!
Ketchup has a weak acid in it, which dissolves the dirt and mold on the coin.

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