I have one half of a wheat penny that looks to be perfectly split open. It's copper with what looks to be a steel disk inside of it, can somebody explain what this is?
It looks like one-half of a magician's coin. The coin is reamed out so that another coin can be inserted, thus creating a heads/heads or tails/tails coin. Chris
As said it is used in a magic trick. The other half, which is missing, is a dime on one side and the other side of the penny on the other side. This allows you to show two coins in your hand, a Lincoln cent and a dime, then close your hand and press the two together forming a Lincoln cent with the dime part hidden inside. You need a special ring attachment to bang the two parts apart before repeating the effect. It is also sometimes called the scotch and soda trick. Here is a video of the effect.
You can get a complete set for about $6 on ebay. If someone lost the penny side I would guess they would be willing to pay a few dollars for what you have. Although there would be no guarantee that the two parts would fit nicely since they were not made together. Go to you local magic shop and ask them. Or post something on a magic forum about having the penny side of a scotch and soda gimmicked coin that you want to sell. But likely it is not worth the effort. Sorry.
First, welcome to the forum, if you read the thread I'm sure you will get the answers you are looking for. Thanks, Jacob