The Nature of Magnets:

Objectives:

    1.    Describe magnetism.

    2.    Describe the properties of magnetic poles.

    3.    Explain the use of magnetic lines of force in relationship to magnetic fields.

    4.    Compare and contrast temporary and permanent magnets.

Resources:

 

Notes:

Properties of Magnets

Magnets are common to everyone.  They stick to our refrigerator, are used to give high resolution images in medicine (MRI) and are an essential ingredient of light.  Magnets can be made and can be found in their natural form.  Natural magnets are from the stone magnetite (loadstone) and were first discovered in the region known as Magnesia (in Greece) nearly 2000 years ago. No matter what type of magnet you have, they all have the property of magnetism.

bulletMagnetism is a force of attraction or repulsion due to an arrangement of electrons.  
bulletAll magnets have magnetic poles.

(www.cmdowns.com/images/ minerals/magnetite.jpg)

MRI of the head and cervical spine (neck)(www.imaginis.com/graphics/ mri-scan/mri-spine.jpg)

Magnetic Poles:

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Place where the magnetic forces are at their strongest

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There are North-seeking and South-seeking poles to every magnet. Otherwise simply known as North and South

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The poles are named after the direction that they point when suspended.

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Like poles repel & opposite poles attract. (Just like electric charges)

   

(www.physics.uiowa.edu/~umallik/ adventure/magnets/poles.gif)

Magnetic Fields:                                             

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A magnetic field is the area in which magnetic forces can act

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Are defined by the magnetic lines of force. (Magnetic field lines)

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The direction is from the north to the south pole.

Animation of magnetic field lines

 

 

 

 

(liftoff.msfc.nasa.gov/academy/ space/bar_magnet.gif)

 

Magnetic materials:

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Natural magnets are made of magnetite

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Most of the magnets that you use have been magnetized

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The process of making magnets is called magnetic induction.

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Temporary magnets are made of soft iron and are easy to magnetize.

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Cobalt, Nickel and hard Iron are used in the production of good strong magnets