Good morning, Thoughts on what has caused the date and letters to look bubbled on this 1973 penny. I think I read somewhere that it could be due to a double die or is it due to a worn die?
As @paddyman98 suggests, probably a damaged coin that smoothed out over the decades of service. Dryer coins that get recirculated tend to gain that appearance.
I don't know where my father got his pennies, but they look pretty good. He died in 1996 and my mother gave them up in 2012. My brother and I split them up. At the time, my brother knew more about coin collecting, but I started getting books or checking them out in our library. Those of us that served in the military probably know more about coin collecting than I did. My brother got tired of answering questions and started sending books to me. I don't know if it is normal to want to buy books about coins instead of watching wrestling. My wife has sequestered me in Dad's old library when I come to see here. I like to read other collector's reviews of their coins on cointalk and Coin World and my Red Book. I started reading Red Book shortly after I bought a few coins the first time. My wife look for them in my library. I'm now buying 2 books each year and try to answer her questions. Most of them I have to get from you folks.
Kim, remember that prior to mid 1982, US cents were made from a mostly copper metal content. Copper, being a soft metal, was/is easy to manipulate, so over the course of handling that coin in circulation, the obverse and reverse get hit by other objects thousands of times, and that "moves" the metal, causing it to spread out and give it the appearance you are seeing on your coin. Hope that helps.
