Taco Sauce Penny Cleaner

Let's Try It

1. 

   Let’s start with the hypothesis of this experiment: Taco sauce is a great penny cleaner. If this is true, then we can use the scientific method to determine the science behind this saucy secret.

2. 

   Place several tarnished pennies on a plate and cover them with taco sauce. Use your fingers to smear the taco sauce all over the top surfaces of the pennies. Remember to wash your hands . . . and don’t lick your fingers because dirty pennies are gross.

3. 

   Allow the taco sauce to sit on the pennies for at least 2 minutes.

4. 

   Rinse the pennies in the sink and look at the difference between the top sides of the pennies that touched the taco sauce and the bottom sides. It’s no myth—taco sauce does the trick.

5. 

   For an easy-to-see comparison, use another tarnished penny and cover only half of the surface of the penny with taco sauce. Don’t smear the sauce around with your finger this time—you want a nice dividing line between the two sides. Let the penny and sauce
   combo sit for a few minutes and rinse. It’s a cool half-and-half penny.

6. 

   Since the hypothesis is true, which of the ingredients in taco sauce is responsible for its cleaning power? Let’s find out . . .
   The list of ingredients on the packet of taco sauce reveals four substances to test: vinegar, tomato paste, salt, and water.

7. 

   Place two equally tarnished pennies on each of four different plates. Use masking tape or a sticky note to mark each plate with the taco sauce ingredient you are testing (vinegar, tomato paste, salt, or water).

8. 

   Cover the pennies with the various ingredients, smear them around with your fingers, and allow the pennies to sit for at least 2 minutes. Be sure to wash your hands.

9. 

   Rinse the pennies from each test plate with water. Which ingredient cleaned the pennies the best?

10. 

    None of the individual ingredients do a good job of cleaning the dirty pennies. In fact, the results are less than impressive. Maybe two or more of the ingredients work together to react against the copper oxide (the tarnish) on the penny. Let’s find out . . .
    Place two equally tarnished pennies on each of three different plates. Make three signs that say “Tomato Paste + Vinegar,” “Salt + Vinegar,” and “Tomato Paste + Salt.”

11. 

    Cover the pennies with each of the mixtures, smear them around with your fingers, and give the ingredients at least 2 minutes to react. Wash your hands.

12. 

    Rinse the pennies under water. Now what do you notice?

13. 

    And the winner is . . . VINEGAR + SALT! But why?