Subject: How does a magnet make a speaker work?

I have bult a simple speaker out of a paper cup some copper wire 
and magnet I found out of a old speaker. How does just a 
simple speaker work? How would this homemade speaker differ from 
the ones made by manufacturing companies? I hope you can answer 
my questions. I have looked in tonnes of places and I am having 
no luck finding anything or I am having a problem understanding 
it. Thank you for your time  

Re: How does a magnet make a speaker work?