What you need :
- Dirty coins (my kids preferred the 5 and 10 centavo ones)
- 1/4 cup White Vinegar
- 1 tsp Rock Salt
- Glass bowl or jar
What to do :
- Slowly pour the vinegar into the jar.
- Add the salt into the mixture.
- Stir until the salt dissolves.
- Drop the coins into the jar, keep stirring, and watch the science happen.
What to expect / why it happens :
The coins come out more vibrant in color and the 1 peso silver coin that had black stuff all over it is now shiny.
There is some pretty fancy chemistry going on in that little bowl of yours. It turns out that vinegar is an acid, and the acid in the vinegar reacts with the salt to remove what chemists call copper oxide which was making your pennies dull. 
Watch out every Saturday for more Science experiments, field trips, and discussions with these two!
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