Magnetism

Magnetism

1. Poles

   • All magnets have north and south poles
   • Opposite poles attract and like poles repel
     • https://www.google.co.uk/search?safe=off&q=breaking+a+magnet&bav=on.2,or.r_cp.r_qf.&bvm=bv.45512109,d.d2k&biw=1366&bih=643&wrapid=tlif136644468433410&um=1&ie=UTF-8&hl=en&tbm=isch&source=og&sa=N&tab=wi&ei=lkpyUbiLIYHU0QWo64C4CA#um=1&safe=off&hl=en&tbm=isch&sa=1&q=magnets+attracting+and+repelling&oq=attracting+and+repell&gs_l=img.3.0.0i5l2j0i24l2.99238.104072.0.106444.21.17.0.4.4.0.259.2079.6j9j2.17.0...0.0...1c.1.9.img.STYlTfF0UvQ&bav=on.2,or.r_cp.r_qf.&bvm=bv.45512109,d.d2k&fp=f0fe323487b2251a&biw=1366&bih=643&imgrc=j1n-1hYavWDb9M%3A%3BAEG0dZ3jFys__M%3Bhttp%253A%252F%252Fstartswithabang.com%252Fwp-content%252Fuploads%252F2009%252F03%252Fnewmagnet.jpg%3Bhttp%253A%252F%252Fstartswithabang.com%252F%253Fp%253D1643%3B640%3B480

2. Changing Magnets

   • Breaking
     • Breaking a magnet makes two magnets. They will both have a north and south pole but they will just be weaker than when they were together
       • https://www.google.co.uk/search?safe=off&q=breaking+a+magnet&bav=on.2,or.r_cp.r_qf.&bvm=bv.45512109,d.d2k&biw=1366&bih=643&wrapid=tlif136644468433410&um=1&ie=UTF-8&hl=en&tbm=isch&source=og&sa=N&tab=wi&ei=lkpyUbiLIYHU0QWo64C4CA#imgrc=czxX5hiLWCRldM%3A%3BM3zZaP_Wrie65M%3Bhttp%253A%252F%252Fwww.splung.com%252Ffields%252Fimages%252Fbarscut.png%3Bhttp%253A%252F%252Fwww.splung.com%252Fcontent%252Fsid%252F3%252Fpage%252Fmagnetism%3B247%3B163
       • This will keep on happening every time you break it.
   • Magnetic Materials
     • When a magnetic material is close to a magnet it becomes a magnet itself. This means a magnet can turn a magnetic item any way round.
       • In the link below, the paperclips have turned into a magnet. If the magnet's side facing the paperclips were north, the paperclips will automatically turn to south. https://www.google.co.uk/search?safe=off&hl=en&q=magnetic+material+into+a+magnet&bav=on.2,or.r_cp.r_qf.&bvm=bv.45512109,d.d2k&biw=1366&bih=643&wrapid=tlif136644489505710&um=1&ie=UTF-8&tbm=isch&source=og&sa=N&tab=wi&ei=bUtyUbamLI-X0QWF-4CwBg#um=1&safe=off&hl=en&tbm=isch&q=paper+clip+and+magnet&spell=1&sa=X&ei=m0tyUcGJOOaW0QXGq4D4DA&ved=0CFAQBSgA&bav=on.2,or.r_cp.r_qf.&bvm=bv.45512109,d.d2k&fp=f0fe323487b2251a&biw=1366&bih=643&imgrc=Q6btwRFv9uVI7M%3A%3B3Z4St_wxA2ExeM%3Bhttp%253A%252F%252Fcontent.mycutegraphics.com%252Fgraphics%252Fscience%252Fmagnet-paper-clips.png%3Bhttp%253A%252F%252Fwww.mycutegraphics.com%252Fgraphics%252Fscience%252Fmagnet-with-paper-clips.html%3B450%3B421
       • This means it has an 'Induced Magnetism'
         • http://www.le.ac.uk/se/centres/sci/selfstudy/mam6.htm Explains Induced Magnetism

3. Types of Metal Found In Magnets

   • Soft Magnetic Materials
     • Pure iron is a soft magnetic material
       • It is easy to magnetise but loses its magnetism easily
       • Iron is used in a electric bell. This is so when it hits the hammer, it looses its magnetism instantly as it is not connected to the magnet.
         • When it reconnects it regains its magnetism. This process creates the ringing noise.
   • Hard Magnetic Materials
     • Steel is an example of a hard magnetic material
       • It is harder than iron to magnetise but it keeps its magnetism much longer.

4. Magnetic Fields

   • Magnetic fields are in the shape of an 8 around a magnet with lines coming out of the middles
     • https://www.google.co.uk/search?safe=off&hl=en&q=magnetic+fields&bav=on.2,or.r_cp.r_qf.&biw=1366&bih=643&wrapid=tlif136639968922210&um=1&ie=UTF-8&tbm=isch&source=og&sa=N&tab=wi&ei=2ZtxUebpIMib0AXtloGQDA#imgrc=OXPuZBFnVSiSWM%3A%3BBUIRp_frWue46M%3Bhttp%253A%252F%252Fwww.tutorhelpdesk.com%252FUserFiles%252Flines%252520of%252520magnetic%252520flux%252C1.jpg%3Bhttp%253A%252F%252Fwww.physicsforums.com%252Fshowthread.php%253Ft%253D673315%3B430%3B310

5. Electromagnets

   • How is it made?
     • To make an electromagnet, you need to have an electric current going through a wire.
       • This would already be an electromagnet but if you add an iron nail to it, it will make it even stronger
     • They are usually made of iron so it will loose its magnetism quickly. Steel would keep it as a magnet for much longer.