We played with coins today for Presidents’ Day, using what we had on hand to determine what would clean coins the best. Initially, we set up our experiment with vinegar, baking soda, and a control (just water).
My daughter hypothesized that the baking soda would clean the best, followed by water, then vinegar.
We poured water into each container and then added vinegar to one, and baking soda to another, leaving the third as just water:
At this point, Daddy came along and suggested we add another variable–”hot sauce”. What a neat idea! My daughter hypothesized that the hot sauce would be better than water but that the baking soda would still be the best cleaning solution.
Now that we have our solutions prepared, we dropped in the corroded pennies:
While the pennies sat in their solutions, we made crayon rubbings of coins, identified the Presidents, symbols, and buildings on each.
Finally, we were ready to remove the pennies and see the results:
The hot sauce was the clear winner. My daughter thought the vinegar shined the penny more than the baking soda, though the baking soda seemed to have removed more of the dirt. The water was the least effective.
Why did the hot sauce work the best?
Well, the hot sauce combines the effective acidic vinegar with salt. Make a vinegar (or juice) and salt solution and you will get the same results!
Check this page out if you are a scientist or very smart high school student to find out why acid plus salt results in the best cleaning solution.
Shared at: Science Sunday