If we leave 4 tarnished pennies in different solutions to clean, then lemon juice will clean the best because the tarnish on pennies is caused by oxidation. Tarnish can be cleaned well by acids. To find out how acidic something is, you use the ph scale. The lower something is on the scale, the more acidic it is. Lemon juice has a ph of 2.2. That is the lowest of our solutions, so it will clean the best.
In our test, lemon juice cleaned the best. It won by 3 points. Vinegar came in second by 5 points. Baking soda came in third by .50 of a point. Salt water came in last, with a score of 3.5 total cleansing. Our results were very varied, like baking soda. In trial one the score was one, in trial two the score was 0, and in trial 3, the score was 3. Although the scores were varied, lemon juice stayed consistently good.
Our hypothesis was correct. Lemon juice did clean the best. This is because it had the highest acidity. We think that the experiment was fairly successful, even though our results were varied. Next time we do this experiment, we will try to make sure the pennies are equally tarnished. Some of the tarnish on pennies were unequal. Some tarnish may even have been different kinds. We are curious to know if it was. We enjoyed this experiment because we learned a lot about chemical reactions and oxidation.