Which Liquid Cleans A Coin The Best?

AFTER

Conclusion-

My data proved my hypothesis right and wrong. Lemon Juice did do the best, getting an average of rating of 7.5! Coming in second was Dish Soap which got an average rating of 7. A 3 way tie which consisted of Water, Cola, and Orange Juice, got an average rating of 5.5. This came to a surprise to me since Cola usually doesn’t clean anything, just makes them worse. Last, Baking Soda Paste got an average rating of only 2.5.

Abstract-

Did you know that most coins circulate for about 25 years until they are too worn to be used! That’s pretty amazing considering the fact that a dollar bill can only last for about 18 months. Coins go way back, way back to 619-560 B.C. Era, where the King of Lydia, Alyattes, were mentioned on all of the coins. Back then, they were made of electrum, silver, and gold. Today, they are made from copper, nickel, and zinc, which brings us to my experiment. For my science fair experiment, I wanted to answer the question of “Which Type Of Liquid Can Clean A Coin The Best?” My type of liquids consisted of Cola, Baking Soda Paste, Orange Juice, Water, Lemon Juice, and Dish Soap. I hypothesized that Lemon Juice would clean a coin the best because of it’s very strong acids.

To do my experiment, I found 24 cups to use. I then filled 4 cups each, one quarter full with each of the cleaning solutions. (4 with Cola, 4 with Baking Soda Paste, 4 with Orange Juice.) Before I placed each type of coin into the liquids, I recorded how worn out they were. I then placed each different type of coin into the cups, and let them soak in the solutions for 36 hours.

36 hours later, I took the coins out and recorded what I saw. I rated them on a 1-10 scale from how well the solutions cleaned the coins, 10 being the best, and 1 being the worst. For the Cola, the average rating it received after the test was a solid 5.5. This was to me, surprising since Cola is usually known as killing teeth, not cleaning them. For Orange Juice, the average rating was a 5.5 tying with Cola. For Baking Soda Paste, the average rating was a 2.5. Baking Soda paste really didn’t show much improvement on the coins. For water, the average rating was again 5.5, tying with both Cola and Orange Juice. For lemon juice, the average rating was a 7.5! Lemon juice, as I thought was going to be the best because of its acids. Last but not least, for dish soap, the average rating was a 7, almost beating out Lemon Juice.

My results showed that strong acids such as Lemon Juice, were clearly the best at cleaning a dirty, worn out coin. This experiment showed that my hypothesis was correct. Lemon Juice was the clear winner, although, dish soap was not far behind. To my surprise Cola didn’t do that bad since it's known as the “destroyer” to teeth, coming in a 3 way 3rd place tie with Orange Juice, and Water. Baking Soda came in last, with only rating of 2.5. My science fair project was very reliable, showing reasonable improvement or non-improvement. The one thing I could change is maybe having coins that are the exact dirtiness as other coins. Coins are not only a part of our money, but our life. We use them every single day, so why not be nice, and give the coins a nice, cool, lemon juice bath.