This is a novelty coin not made by the US mint and has no collectible value.
A fake.
A two-headed penny.
$14,500
The head's side of the penny is heavier because, the indentions on the head's side happens to make it slight heavier but I have tested this project out and it is not a myth it is head's.
Nothing- return it to the store where you got it. These have been showing up in penny rolls. it is play money.
They cost about $8.95 at novelty shops. Look at it with an 8X magnifier and you should be able to find the seam where one coin was hollowed out and another ground down to fit inside.
$8 - $10 at a novelty shop. $2 - $3 on eBay.
There's a good image of both sides at the link below
It's a trick or magic coin and has little or no value.
The Canadian "double-headed" cent is equal to the British One Penny. The Canadian one "cent" is equal to the British 1/2 penny (so a British penny is 2 cents or 1 double-headed cent). When first issued, the Canadian government had them struck to a standard of 100 coins to the pound of bronze rather than the the British standard of 80 coins to the pound of bronze. The first 1858 issues, however, were unpopular and originally had to be sold at a discount. It is believed the Canadians joined the two cents together to make them equivalent to the British Penny.
Not really, the better expiriment would be if you used both sides of t he penny and compare all of your trials.