Coca-Cola Mystery
What if you put pennies in Coca-Cola?
Hypothesis:
Research
From 1783 to 1837 the penny was pure copper
From 1837 to 1857 the penny was made of bronze (95% copper and 5% tin and zinc)
From 1857 to 1863 the penny was 88% copper and 12% nickel, giving the penny a white appearance
From 1864 to 1962 the penny was back to bronze
In 1943, the penny was made of zinc-coated steel, because of the war effort needing the copper
In 1962, the penny was made of 95% copper and 5% zinc
In 1982, the penny's makeup changed to 97.5% zinc and 2.5% copper
All this information is from the US MInt's website
The reason that the penny was changed to mostly zinc is because the value of a penny sank until the copper contained in it was worth more than a penny.
This information came from a book called The Elements, by Theodore Gray
Coca-cola is acidic because the carbon dioxide gas used to preserve it dissolves in the solution and forms carbonic acid. The pH ranges from 2.5 to 4.2.
This information comes from ask.com "why is coke acidic?"
Materials
5 Pennies
1-1976
1-1977
1-2000
1-2013
Coca-Cola
Container
Procedure
2 Put them in order by year
3 Put the pennies in a container
4 Put 10 oz of Coca-cola in the container
5 Wait for 2 hours
6 Check the pennies for changes
7 Write down what you see
8 Repeat steps 5 through 7 for 24 hours
9 After 24 hours take pennies out of cola
10 Write down final appearance of pennies
Observation
all coins went in the cola
11:30 am
1973-no change
1977-no change
1978-no change
2000-no change
2013-no change
1:30 pm
1973-color has change penny looks older
1977-color changed looks darker
1978-no change
2000-no change
2013-no change
3:30 pm
1973-color is darker
1977-color is darker
1978-no change
2000-no change
2013-no change
5:30 pm
1973-color is darker
1977-no change
1978-no change
2000-no change
2013-no change
7:30 pm
1973-color is lighter
1977-color is lighter
1978-color is dark looks dirty
2000-no change
2013-no change
9:30 pm
1973-no change
1977-color is lighter
1978-still dark, looks rusty
2000-no change
2013-no change
11:30 pm
1973-color is lighter but penny is dull looking
1977-color is lighter
1978-penny is dirty and rusty looking
2000-penny is darker
2013-no change
1:30-5:30 sleeping
7:30 am
1973-lighter
1977-penny is lighter
1978-penny is rusty
2000-lighter
2013-no changes
9:30 am
Remove pennies from cola
1973-looks cleaner not shiny
1977-looks cleaner not shiny
1978-dark rusty looking
2000-looks clean not shiny
2013-no changes
Results/Conclusions
The 1977 penny is still copper color its cleaner but not shiny.
The 1978 penny is rusty looking I can still see that it is copper color.
The 2000 penny is brighter but not shiny.
The 2013 penny has not changed.
The coca-cola did not melt the copper off the pennies. The cola made the dark colored pennies cleaner looking. The pennies are still copper color and I can still see the pictures.