MAGNETIC FIELDS

 

       One of the topics I learned in chapter 30, magnetic fields, is ferromagnetism. Ferromagnetism is a strong magnetic effect exhibited by the atoms of certain elements, notably iron. It is the cause of the magnetic field of commonly used magnets. It is the basis of the most familiar type of magnetic devices. For example seeing a magnet affixed to a refrigerator door. The three common elements that exhibit ferromagnetism are iron, nickel, and cobalt. Ferromagnetism is caused by the property of electrons known as spin, the angular momentum of an electron. Even though all matter has electrons, most materials fail to exhibit ferromagnetism because in most materials, the spin of each electron cancels out the spin of another electron in the same atom with which it is "paired." As a result, there is no magnetic field.

       The exterior of a refrigerator is typically not magnetic, yet if it is made of ferromagnetic metal, magnets will stick to it. Magnets will stick to the refrigerator because the magnet induces a temporary magnet in the refrigerator's surface. The actual magnet, and refrigerator's exterior then are attracted to each other. The picture of the lady on the calender sticks to the side of my brand new refrigerator. That is an example of ferromagnetism. However, the shiny silver part of my new refrigerator fails to attract magnets. That part of the refrigerator is not made up of either iron, nickel, or cobalt. My old white refrigerator was able to attract all the magnets in the other picture below.

 



  

Side of the refrigerator! Magnetic calnder

Magnets galore! I bought the Vegas one



My brand new shiny silver refrigerator