MadSci Network: Physics
Query:

Re: why does a magnetize nail don't have an equal amount on both ends of nail.

Date: Thu Mar 24 12:54:23 2005
Posted By: Norm from Georgia, Staff, Materials Engineer, U S Air Force Materiel Command
Area of science: Physics
ID: 1111643256.Ph
Message:

The moderator has suggested that it may involve the symmetry of the nail, 
and I would tend to agree that it may be part of the answer.  Since the 
amount of strength would be dependent on the lines of flux divided by 
area, the larger area of the head of the nail should have the 
lesser strength.  And this could be confirmed by cutting the tips off the 
ends and see if the intensities balance out.

Of course, if it turns out that the pointed end was not the 
stronger end, I have (as usual) a back-up theory…

Rubbing the nail is not the best way to produce a uniform field.  In 
fact, if the entire length was not rubbed, then the magnetic field of the 
remainder might fall off significantly.  Of course, if only one end 
(pole) of the original magnet was used to magnetize the nail, then the 
side rubbed would be of one magnetic orientation, with the unrubbed 
taking on the other.  In fact, if only one side of the shank of the nail 
was rubbed, end to end, then the tips might have little polarity at all.

The important thing to remember is that the intensity of the field are 
depended on the closeness, and orientation, of source of the magnetizing 
forces, whether a coil or a permanent magnet, and the cross-sectional 
area and geometry of the area of interest.

BTW, the use of a compass to measure the strength was a creative way to 
do it.

Another way is by seeing how many small ferromagnetic parts, such as 
paperclips, can be lifted by the magnet, preferably end to end.  This is 
particularly applicable when determining the effect of the number coil-
turns versus current versus voltage (determined by the number of 
batteries used in parallel or in series, respectively) on the magnetic 
field generated on a ferromagnetic rod.




Current Queue | Current Queue for Physics | Physics archives

Try the links in the MadSci Library for more information on Physics.



MadSci Home | Information | Search | Random Knowledge Generator | MadSci Archives | Mad Library | MAD Labs | MAD FAQs | Ask a ? | Join Us! | Help Support MadSci


MadSci Network, webadmin@madsci.org
© 1995-2005. All rights reserved.