Why Do Pennies Turn Green?

Have you ever noticed that some old pennies look almost…green? In this experiment, use vinegar and salt to get to the bottom of how and why pennies turn green.

Have you ever noticed that some old pennies look almost…green? In this experiment, use vinegar and salt to get to the bottom of how and why pennies turn green.

Using everyday ingredients and tools from your kitchen cabinet, embark on a hands-on process that prompts you to ask questions, mix compounds, and analyze materials like a scientist at the Museum.

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Materials
- At least 5 pennies
- Vinegar
- Salt
- Plate or shallow bowl
- Paper towel
- Notebook or piece of paper
- Writing utensil

Instructions
- Place some shiny new pennies on a paper towel in a shallow bowl or plate. In a notebook, record what you notice about them. What color are they? How do they feel in your hands?
- Sprinkle some salt over the pennies and pour just enough vinegar to get the paper towel wet.
- Leave them for 24 hours.
- After this time has passed, look at the pennies again. Have they changed color? If you handle your pennies, make sure to wear gloves, just like scientists at the museum!

Reflection
How has the vinegar and salt changed your penny? What do you think caused this change?


Chief Digital Officer: Douglas Hegley
Executive Producer: Sarah Wambold
Director/Writer/Producer: Emma Vecchione
Producer: Rachel Smith
Project Manager: Maria Kozanecka
Animation Direction: Lisa LaBracio
Stop Motion Animation: Lisa LaBracio
2D Animation: Luca Mancuso
Prop Fabrication: Lisa V. Bergmann, Anna Samo
Narrators: Roselin Lopez
Episode Consultants: J-F De Laperouse, Marco Leona
Education Consultants: Darcy-Tell Morales
Original Music: Austin Fisher
Sound Mix: Dave Raymond
Production Design: Aurola Wedman Alfaro
Rights and Permissions: Julie Zeftel

Head of a ruler, ca. 2300–2000 BCE
Mesopotamia.
Copper alloy, 13 9/16 x 8 3/8 x 9 3/16 in. (34.4 x 21.3 x 23.3 cm).
Rogers Fund, 1947 (47.100.80)

Bronze chariot inlaid with ivory, ca. 2nd quarter of the 6th century BCE
Etruscan.
Bronze, ivory, total H. 51 9/16 in. (130.9 cm) length of pole 82 1/4 in. (209 cm).
Rogers Fund, 1903 (03.23.1)

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Bronze chariot inlaid with ivory, Bronze, ivory, Etruscan
Etruscan
2nd quarter of the 6th century BCE
Head of a ruler, Copper alloy
ca. 2300–2000 BCE