Cleaning Pennies With Taco Sauce: A Fun Science Project With Your Kids
Are you looking for a fun and easy science project that engages your kids?
Pennies are great to collect and use for art projects. But you can also use the process of cleaning pennies for a fun science experiment.
In this article I’ll show you how to combine a few dirty pennies with ingredients found in your kitchen to do a science project that will knock your kids’ socks off.
Why Use Taco Sauce to Clean Pennies?
Because you can. It’s amazing what you can do with ingredients you find in your kitchen, and taco sauce is just one fun option. Taco sauce does a great job of cleaning pennies, and the process is quick and easy.
Whether you need a great idea for your kids’ science project or just want something fun to do with all of those grungy pennies, your family is sure to enjoy this experiment.
Do your kids like to collect coins they find on the street?
With this project, you can make coins sparkle, and then save them for a rainy day or use them for a fun art project.
Here are a few fun things you can do with clean pennies:
- Using a white background, make a penny picture of a face, house or other design
- Glue pennies on cardboard to make a penny coaster
- Decorate a plain picture frame by attaching pennies
- Make tap shoes
In this article, we’ll follow the steps as if we are doing a science fair project. However, feel free to use these instructions to clean those pennies so they are ready to use for whatever reason you decide.
#1: Do a Quick Test
Ask your kids the question: “Does Taco Sauce clean pennies?” Have a conversation and come up with reasons why it will or will not work.
Next, it’s time to determine if taco sauce really works as a penny cleaner. Drop a few dirty pennies on a plate and cover them with taco sauce.
Check out my demonstration video.
Smear the taco sauce on the top surfaces using your fingers, but don’t lick them. Dirty pennies are disgusting and taco sauce is hot.
Leave the sauce on the pennies for about 2 minutes.
Rinse the pennies in the sink and compare the taco sauce side to the untouched side.
You can now answer the question. Yes, taco sauce definitely cleans pennies.
You can also try carefully dropping the taco sauce on only half of the surface of the penny. Don’t use your finger to rub it around. Keep one side covered with sauce and one side untouched. You want a nice dividing line between the two sides.
Rinse the penny and compare the “washed” and “unwashed” halves.
#2: Design Your Experiment
Now that you’ve determined that taco sauce works on dirty pennies, it’s time to design and plan your science project.
Start by looking at the ingredients in taco sauce: vinegar, tomato paste, salt and water.
Next, ask a question and make a guess (hypothesis) as to the answer.
In this experiment, we are asking the question, “What taco sauce ingredient is responsible for cleaning pennies?”
The hypothesis can be anything like “I hypothesize the tomato paste will clean the best because it is acidic.” Don’t sweat this—it is your guess and you won’t be graded on it.
Then plan how to test your hypothesis. Develop a materials list and procedure for completing the experiment. What will change and what will stay the same? These will be your variables.
#3: Test Your Hypothesis
Now that you have a plan, it’s time to test your hypothesis. What you are going to do is test the ingredients in taco sauce individually to find out which one works to remove tarnish. Make sure you take notes along the way.
Place the four plates on a table. Use masking tape or sticky notes to mark each plate with a different ingredient (variable) that you are testing: vinegar, tomato paste, salt and water.
Place two equally tarnished pennies on each of four different plates.
Cover each set of pennies with the noted ingredient.
Next, smear them around with your fingers. Be sure to wash your hands afterward.
Now, allow the pennies to sit for at least 2 minutes.
Rinse the pennies from each test plate with water. Which ingredient or ingredients cleaned the pennies the best?
You will discover that none of the individual ingredients did a good job of cleaning the dirty pennies.
Did you choose one or multiple ingredients for your hypothesis? Was your hypothesis wrong? If so, don’t panic. Science is all about experimenting.
#4: Test Another Hypothesis
Let’s try another hypothesis. Here’s a hint: maybe two or more of the ingredients work together to react with the copper oxide (the tarnish) on the penny.
Time to revamp the project.
Wash three plates and, again, lay them out on the table.
Use masking tape or sticky notes to make three signs: “tomato paste + vinegar,” “salt + vinegar” and “tomato paste + salt.” Put them on the plates.
Note: Try different combinations of ingredients to find which combo is responsible for cleaning the penny. Keep in mind that you don’t need to stop with our three recommendations. What other combinations can you make and test?
Place two equally tarnished pennies on each of three different plates.
Cover the pennies with each of the mixtures, smear them around with your fingers and wash your hands. Then give the ingredients at least 2 minutes to react.
Now, rinse the pennies under water and see which combination(s) worked.
It’s the vinegar and salt combination!
#5: Review the Results
The taco sauce penny cleaner experiment is a demonstration of scientific inquiry—ask a question, run tests, ask another question, run tests, ask another question and run tests until a conclusion is reached.
Good science fair projects shouldn’t focus on whether the hypothesis was correct, but instead leave you with more questions than it answered.
So, how did it work? Neither the vinegar or salt alone worked to clean the penny, but mixing them together worked.
The chemistry behind the reaction is somewhat complicated. When the salt and vinegar are mixed together, the salt dissolves in the vinegar solution and breaks down into sodium and chloride ions. The chloride ions then combine with the copper in the penny to remove the tarnish (copper oxide) from the surface of the penny.
It is also well-known that a mixture of lemon juice and salt does a good job of removing tarnish from metals and pennies. (Hint: this may be another great science fair project.)
If you remember, the first hypothesis I suggested was the tomato paste, because it is slightly acidic. It may contribute slightly to removing the copper oxide coating and may do more than the other ingredients individually, but the vinegar and salt are the real power ingredients. That’s ok. We made a guess based on what we knew and then tested it.
Some final thoughts….
Whether you are putting together a stellar science fair project or cleaning pennies for fun, remember the basic steps: ask a question, develop a materials list, take an educated guess as to the answer (make a hypothesis), write down the steps (process), test your hypothesis, if necessary test another hypothesis (experiment), analyze your results, make conclusions and ask more questions.
What do you think? How could you extend the experiment to try to find more answers? Did this activity cause you to wonder about something else entirely? Could you create a new experiment based on your new questions? Please post a comment or photo below.
Images from iStockPhoto.
Steve Spangler is an author, teacher, toy designer, Emmy award-winning television personality and creator of a huge soda mess. His appearances on television demonstrate his passion for making learning fun. Other posts by Steve Spangler »