Magnetism

Posted on November 20th, 2010

Magnetism is one of the fundamental forces of physics and the Lab Ratz spend a great deal of time investigating the properties and applications of magnetism.

While the magnetic force affects all elements differently, iron is one of those most strongly affected.  We can magnetize almost any object that contains iron by lining up the atoms to spin in the same direction.  This can be done either by stroking an iron object repeatedly with a magnet or by passing an electric current around the object.  The magnetic fields generated by either a magnet or an electric current will “Pull” on the atoms of iron in the direction of the strokes or current, causing them to spin in that direction and thus magnetizing the object.  This can be done at home with a refrigerator magnet and any iron object – A butter knife, paperclip, scrap metal, etc.

ATTENTION LAB RATZ:  WE NEED YOUR HELP!

We are trying to determine what iron object will make the best permanent magnet.  During Lab Ratz programs we usually use steel paperclips to make permanent magnets.  But, we discovered that 12″ steel/iron bars made much stronger magnets and took much less time to make.  We hypothesize that the more iron atoms in an object, the easier it is to induce magnetism in the object – Since there are more atoms, you are more likely to make more of them spin.  So, what we are asking the Lab Ratz to do is:  Help us to figure out what items make the best magnet. 
     
Use the same procedure described above – Stroking the iron object with a permanent magnet to induce magnetism in the iron object – and test the strength of your newly-made magnet by picking up paperclips with it.  Count how many paperclips can be lifted at one time to determine how strong the magnet you made is.  Then, if possible, weigh the object that you used to make the magnet to get a rough idea of how much iron is in the object.  Also, try to count how many times you stroked the iron object to magnetize it.  Then, “Publish” your data and your results to Facebook – Make sure you are friends with us so that we can see it – And we will copy all of the data that is sent in and post it here so that all of you young scientists out there can view the results and help us to draw conclusions.  We will be using the findings from this experiment to improve our “Magnetism and Magnets” activity!  So, you have a chance to help the Lab Ratz Science Club improve a program by putting your science skills to work!  BE SURE TO ASK AN ADULT BEFORE YOU START EXPERIMENTING OR WHEN USING FACEBOOK.  Many thanks and happy experimenting! 

An interesting application for a homemade magnet is a homemade compass.  The core of Earth is made of mostly iron and therefore the planet itself is a giant magnet.  If you can find a way to make your homemade magnet move freely, it will naturally line up between the magnetic poles of the Earth with one end pointing to the north and the other to the south.  One simple way to allow free movement of your magnetic compass needle is to make it float.  But, since iron is much denser than water, you will need to attach it to some other, less dense material.  Be creative and experiment with different methods of constructing your compass and different methods of magnetizing your iron object.  Try different things and see what works best.  EXPERIMENT!  Give it a shot and see what you can do.

Any time a scientist does an experiment they will use what is called a “Control” to help them verify their results.  The control in an experiment gives the scientist a typical situation to compare what they are testing against.  For example, if you were studying how rats respond to loud noises you would expose some rats to noise but you would also have to have some rats that you did not expose to noise so that you could see how they normally behave first so that you would know if anything changed when they heard the noise.  Using a non-magnetic object as a control is a good way to verify that your compass actually works.  Build an identical device but use a similar but non-magnetic object for the needle.  If your magnetic needle consistently points in the same direction but your non-magnetic control compass does not, you can be pretty sure that you have been successful.

Be sure to post the results of your experiment to our Facebook page when you are done so that other Lab Ratz can see how you did it and try it for themselves.  Include a detailed description of what you did and how you did it, as well as what you used as your control and what your results were.  Have fun!