Which liquid cleans pennies the best?

5th Grade Science Fair Project

Problem

• Which of the five liquids used will make these pennies the cleanest and shiniest?

Purpose

• To determine which liquid will make the pennies the cleanest.

Hypothesis

• The penny cleaned with cola will be the cleanest.

Research

• Before 1982, pennies were made of pure copper.• After 1982, pennies are made of zinc core with a thin

copper plating.• Pure copper pennies look dirty because the copper

mixes with the oxygen in the air and makes copper oxide.

• All 5 pennies I am using are from before 1982.

Materials• ½ cup measuring cup

• 5 clear plastic cups & 5 pennies

• ½ cup of each liquid: coffee, cola, grapefruit juice, banana pepper juice & pickle juice

• bowl of clean tap water

• Pen, marker, paper & camera

Procedure/Experiment• Pour ½ cup of each liquid into clear cups

• Take picture of pennies before dropping into liquids

• Drop one penny into each cup of liquid

• Wait 15 minutes

• Take each penny out and rinse in bowl of clean tap water

• Take picture of clean pennies after rinsing

• Take notes of which is the cleanest, next to cleanest and etc…

Procedure/Experiment

Results

Results Best to worst:

☼ banana pepper juice☼ kosher dill pickle juice

☼ grapefruit juice☼ cola

☼ coffee

Conclusion

• My hypothesis that the cola would clean the penny the best was incorrect. In fact, the cola was in 4th place as a cleaner. My project clearly shows the banana pepper juice was the best cleaner. The pickle juice in 2nd place did a better job than the 3rd place grapefruit juice. And last, I saw no change on the penny that was in the 5th place coffee.