With everything going on, it is nice to find something amusing. Over the weekend, I wanted to listen to a couple of podcasts. I reached into my pocket for the case containing my wireless earbuds and found something came along for the ride.
Stuck to the magnetic closure was a coin. A closer look found the coin is a 1978 Canada 10-pent coin. Or that is what the coin appears to be.
The Canada 10-cent coin is slightly larger than the U.S. dime (18.03 mm versus 17.91 mm), and today, the Canadian coin is made of plated steel. But this is a 1978 coin and may not be steel. While investigating the coin’s specification, it is supposed to be made of nickel. I thought nickel was not magnetic. Time to review my basic science
Nickel is one of the transition metals, an element used to form bonds with other elements. While I let you explore the chemistry on your own, let us say that it mixes well with other elements to create valuable compounds. In numismatics, nickel provides the silver color on many base metal coins.
But that does not explain why the coin stuck to my wireless earphone case.
I found that nickel is a ferromagnetic metal, meaning that it can become magnets or be attracted to magnets. Nickel is not naturally attracted to magnets or easily magnetized. But nickel is one of only four elements that can be magnetized easily at room temperature. The other three are cobalt, iron, and gadolinium.
For help, I turned to a high school chemistry teacher to refresh my memory. During the refresher lesson, I flashed back to the high school chemistry demonstration on magnetism, creating a magnet from a ferromagnetic item.
While the coin was in my pocket, the coin rubbed next to the magnet. The rubbing caused the nickel atoms to become orderly that turned the coin into a magnet. The Canadian ten-cent coin that stuck to the earbud case could pick up a straight pin to test the theory.
But why won’t any of my United States coins turn into a magnet in my pocket?
Since U.S. coins are made up of an alloy of 75-percent copper and 25-nickel, the copper and the nickel’s strong bond with the copper stops the ferromagnetic process. It would take a very strong magnet to order the nickel atoms in a U.S. coin to turn it into a weak magnet.
Not only can coins teach history, but they can also teach chemistry.