how does a magnet attract a paperclip ?

Since this is not my area of expertise, I searched Google under the key words "magnetism" to get these possible sources:

http://en.wikipedia.org/wiki/Magnetism
http://www-istp.gsfc.nasa.gov/Education/Imagnet.html
http://www.school-for-champions.com/science/magnetism.htm
http://www.zephyrus.co.uk/magnets.html
http://my.execpc.com/~rhoadley/magindex.htm

In the future, you can find the information you desire more quickly, if you use appropriate key words to do your own search.

I hope this helps. Thanks for asking.