What is the needle in a homemade compass made out of?

Answer 1

Any magnetized object that can be floated on water or oil with very little friction will work.

The ones that work best are things like magnetized straight-pins and sewing needles.

I have a home-made compass in my office. I cut the straight part out of the bottom

of a metal coat-hanger, magnetized it, and hung it balanced from a piece of thread

taped to the ceiling. For relaxation that only an Engineer could appreciate, I like to

give it a gentle spin on the end of the thread, then sit back, and watch it oscillate

back and forth and finally come to rest pointing north again. In this way, I can kill

an hour whenever I want to.