STEM FAIR PROJECTProject title: DIRTY PENNY CLEAN

Student Name: Jacob Aryee

STATEMENT OF THE PROBLEM• Which solution will clean a dirty penny

better?

RESEARCH• Pennies:– 30 million pennies are produced each day!

– A picture of the Lincoln Memorial is on the back of the penny (since 1959)

– Pennies are produced at the US Mint in Philadelphia (GO EAGLES!!!) and Denver

– If former President Lincoln were alive today, he would be 202 years old

VARIABLES• Controlled variables: Amount of liquid (1

cup), size of container (plastic cup), length of time in liquid (5 minutes)

• Independent variable: Cleaning Solution (e.g. cleaning agent added to water)

• Dependent variable: The cleanliness of the penny

HYPOTHESIS• I predict that the pennies will clean better

with the laundry detergent and water because the buttons on my jackets, jeans and shorts are always clean after my mommy washes them in the washing machine. I believe the buttons on my jackets, jeans and shorts are made of the same metal as a penny.

MATERIALS• 3 dirty pennies

• 3 plastic cups

• Water

• A teaspoon

• Arm & Hammer Free & Clear laundry detergent

• White vinegar

• Salt

• Arm & Hammer baking soda

PROCEDURE• Collect 3 dirty pennies

• Place dirty penny in cups A, B and C

• Pour 1 cup of water into plastic cup A

• Pour 1 teaspoon of laundry detergent into cup A and stir

• Pour 1 cup of water into plastic cup B

• Pour 1 teaspoon of baking soda into cup B and stir

• Pour 1 cup of white vinegar into cup C

• Pour a teaspoon of salt into cup C and stir

• Allow each penny to soak in the solution in each cup for 5 minutes

• Remove pennies from each cup carefully and inspect cleanliness of pennies

• Record Data

DATA/OBSERVATIONS

• Note: To measure, we decided to come up with our own scale to show the effectiveness (how well) of the solutions. 1 is the highest and simply means the solutions did in fact clean a good portion of the penny. 0 indicates that the solution did not alter the appearance of the penny.

CONCLUSION• The results indicated that vinegar and salt

was the best cleaning solution for cleaning a dirty penny. I thought that detergent would work since it cleans my dirty clothes and my buttons are always clean after washing. But detergent didn’t really make the penny very clean. With the salt and vinegar solution, 1 side of the penny became really shiny. The other side got shinier too, but it also developed a black mark which was strange.

DETERGENT

Water! Detergent!

DETERGENT RESULTS

BEFORE AFTER

Not bad. But let’s see if we can get it cleaner!

BAKING SODA

Baking Soda!

Mixing!

BAKING SODA RESULTS

BEFORE AFTER

WONK WONK WONK An epic fail!

VINEGAR & SALT

Salt!Vinegar!

VINEGAR & SALT RESULTS

BEFORE AFTER

Look at that shine!

WORKS CITED

• Interesting Egg Fact. http://didyouknow.org/eggs/