Testing the strength of an electromagnet....

[Ave V]

For our physics class we have to design an experiment investigating the factors affecting an electromagnet's field strength. I have decided to investigate the number of coils in the wire. My only problem is, I'm not sure how to measure the field strength. Our teacher gave us two things which we could use in order to do it: a small compass and a paperclip. People in my class have already suggested the obvious ways: seeing how many clips it picks up, or at what distance a paperclip is affected by the magnet, but our teacher said these ways were not easy to control and that we should keep thinking. I can't think of any other way to use these items in a better way and I really want to know.

 

[Dr. Courtney]

One can use a compass to determine at what distance the field of a source is equal to the Earth's field.

Think about how using vector addition.

 

[Merlin3189]

suggested the obvious ways: seeing how many clips it picks up, or at what distance a paperclip is affected by the magnet, but our teacher said these ways were not easy to control and that we should keep thinking.

1 - Obvious? Well there's nothing wrong with doing things the best way. Thinking up an obscure but ineffective method would not be a good idea. Just evaluate ideas on their merits.
2 - So he says, " at what distance a paperclip is affected" is not ok? Since he gave you a paperclip, presumably he doesn't want it to be unaffected. So I can only conclude he thinks "at what distance" is the wrong way. What else could you measure about a paperclip being affected by a magnet? (BTW in what ways can a magnet affect a paperclip?)
3 - You mention a small compass, but don't mention any ways of using that.
4 - "and I really want to know. " I don't know what other PF people think, but I don't think there is The Answer to a question like this. Even when you Know The Answer someone else could come along and think up another (better?) idea. Just think about what you could do, what the strengths and weaknesses of these ideas might be, then post your thoughts and get them critiqued here. That might lead you to better ideas.

 

[andrevdh]

It seems the keyword is "field strength".
So what do you know about a magnetic field?