I remember when I was a child we made an electromagnet in school, and I thought it was the coolest thing out there. For parts back then we used a nail, a 6v battery, and copper wire. So thats what I went in search of for this project.
After showing my daughters the difference between a magnet and a basic nail we gathered some paper clips and the extra nails to show what the electromagnet can do. We knew from trying with a regular magnet that the nails and the paper clips could be picked up, we also saw that a regular nail could not pick up anything.
After I had it setup I fully intended to let my daughter hold the nail (I guess I forgot how hot it gets) So for this project it was mostly me, as I had the girls but things in front of the magnet and they watch it attract to the now copper wire covered nail. Let me tell you it generates heat, so had to hold it carefully also.
I am sure you can probably use a smaller battery but I was going off memory for this project.