Grade Levels:
Preschool
Elementary

Estimated time to complete this project:
Two Days.

Materials:
8 ædirtyÆ pennies
apple juice
orange juice
grapefruit juice
grape juice
lemon juice
eye dropper
5 glass jars
paper towels
pH paper with color chart
log book and pencil

Instructions:
1) research what metal a penny is made from. Is it pure copper or a combination of alloys? Explore the scientific reasons for copper oxidizing and turning green (site examples of buildings in your town that have a roof made of cooper, talk about the Statue of Liberty). Have a discussion of what kind of agent would need to be used to æcleanÆ the copper. After research, your child should come to the conclusion that an acid-type cleaning agent would best bring out the copper color. The hypothesis then becomes that an acidic fruit juice will work best.

2) Prep your five jars by filling each with a different juice. Label jars.

3) Take the pH paper and dip one piece into each jar, match the pH paper with the color chart, one jar at a time, and record your results in your logbook. Your child will be able to see which juice is more acidic and which is more alkaline. Of the acid fruit juices, your child can now hypothesize which of these juices will work the best.

4) Place a penny in each jar and let sit overnight.

5) Dump out the juice in the sink and lay pennies out on separate paper towels to record.

6) Results should show that the acidic fruit juices cleaned the pennies the best.

7) Your child can take it a step further by laying out three ædirtyÆ pennies on separate pieces of paper towel and adding one drop of grapefruit, lemon and orange juice to each separate penny to see which of these three juices cleans the penny the fastest.

8) Record results.

9) Your child can make a color chart graph designating the acidic levels of each juice.

10) Another chart can rate which juice cleaned the penny the best, as well as graph which cleaned it the quickest.