Try This Penny Cleaning Science Experiment for Kids (Vinegar & Salt)
In this easy STEM activity, kids will discover how everyday ingredients, like vinegar and salt, can transform a dull, dirty penny into one that looks shiny and new. The Penny Cleaning Trick is a perfect hands-on way to introduce young learners to basic chemistry concepts while encouraging observation, prediction, and scientific thinking.
This simple science experiment is ideal for preschoolers, kindergarteners, and early elementary students. Adult supervision is recommended.
Questions to Ask Your Child During the Experiment:
- What does the penny look like before we start?
- What changes do you notice while the penny is in the mixture?
- Why do you think the penny looks different afterward?
- What other objects might change when cleaned this way?
These questions help children practice observation, prediction, and scientific thinking.
What You’ll Need for the Penny Cleaning Experiment:
- Old, tarnished pennies
- White vinegar (about 1/4 cup)
- Salt (about 1 teasopoon)
- A small bowl
- A spoon
- Paper towels
Instructions for the Penny Cleaning Science Experiment:
Step 1: Add Salt to the Vinegar
1
Pour a small amount of white vinegar into a bowl. Add about a teaspoon of salt to the vinegar.
Step 2: Stir Well to Dissolve the Salt
2
Use a spoon to stir the vinegar and salt together. Keep stirring until the salt dissolves into the liquid. This creates the special solution that will help clean the pennies.
Step 3: Pour the Mixture Into the Bowl
3
Place the dirty pennies into a larger bowl or container. Carefully pour the vinegar and salt mixture over the pennies until they are covered.
Step 4: Watch the Color Change
4
Let the pennies sit in the mixture for a short time. Watch closely as the pennies begin to change color.
Encourage kids to observe what’s happening and talk about what they see.
Step 5: Compare the Shiny Penny
5
Remove the pennies from the mixture and place them on a paper towel to dry. Compare a cleaned penny with a dirty one. The difference is easy to see!
Video Instructions
Why Does Vinegar and Salt Clean Pennies?
Pennies are made mostly of copper. Over time, copper reacts with air and forms a dull coating called tarnish that makes pennies look dirty.
The vinegar and salt work together to create a chemical reaction that removes the tarnish. The vinegar works as an acid that loosens the tarnish and the salt helps to break the tarnish apart. This chemical reaction reveals the shiny copper underneath, making the penny look new again.
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