In the Senior Room we recently learned about electromagnets. You can see them at work in cranes in scrap-yards where they lift scrap metal. They are also part of M.R.I. scanning machines.
We learned that you can make certain materials into magnets by running a current through them. We used an iron nail, at first it would not life the paper-clip but once we attached it to a battery via wire it became magnetic and lifted the paper-clip. It was a great activity but we had to be careful as both the battery and the iron nail began to heat up as the current ran through them.