I needed to create electromagnets that could lift a platform. I started experimenting by using 32 gauge wire wrapped around a screwdriver. This did not have nearly enough lifting force. I tried to wrap it around a bolt instead, but this did not help. 

I used this formula to try to refind my electromagnet. I found that I need wires of less resistance. Thus, I used 24 gauge wire wrapped around a bolt 500 times. This created about 10 N of force.