SPH 3 USPH 4 C DOMAIN THEORY OF
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SPH 3 U/SPH 4 C DOMAIN THEORY OF MAGNETISM
TYPES OF MAGNETS � Permanent � Temporary (materials that can be made magnetic but eventually lose their magnetic properties)
INDUCED MAGENTISM � Materials containing IRON, NICKEL, or COBALT can be magnetized when placed in/near a magnetic field.
FERROMAGNETISM � Ferromagnetic Materials: these materials include iron, nickel and cobalt (and alloys of these metals). � Two Types: Soft & Hard Ferromagnetic Ex. Pure iron – remains magnetic only in the presence of a magnetic field. TEMPORARY Magnet Ex. Steel (an alloy)– remains magnetic even after the magnetic field has been removed. SEMI-PERMANENT Magnet
MAGNETIC FIELD STRENGTH � The magnetic field strength is a fundamental force called the: Electromagnetic Force � It is incredibly strong … it is the second strongest force of the 4 fundamental forces. � Much, much stronger than the gravitational force.
DOMAIN THEORY OF MAGNETISM � What is theory of magnets? � � � Magnets have a North and South pole (N & S) All magnets are made of many smaller magnets called dipoles (2 poles) Each dipole can interact with the other dipoles in the material, if the dipoles line up in a single direction, then small magnetic domains are created; these act like tiny bar magnets In a strong magnetic field all of the small magnetic domains line up forming one large magnet with N and S poles Breaking a magnetic in two; domains remain aligned and two new magnets are formed. Disrupting the alignment of the domains so that the dipoles are randomly distributed in demagnetization.
DOMAIN THEORY OF MAGNETISM � Magnetic � Result: Domains UNALIGNED Regions or Not Magnetic overall Domains Individual Dipoles in a domain
DOMAIN THEORY OF MAGNETISM � Magnetic � Result: Domains ALIGNED Bar magnetic is formed Regions or Domains Individual Dipoles in a domain
DOMAIN THEORY OF MAGNETISM � Demagnetization: when you disorder the alignment of the magnetic domains you will cause the material to not be magnetic overall. This can be done in 2 ways: � Physically disrupt the alignment by repeatedly striking the material � Disrupt the alignment by heating the material to a very high temperature.
DOMAIN THEORY OF MAGNETISM � http: //www. youtube. com/watch? v=9 KOLu 9 Mx. Fq 8 Need more help understanding the domain theory of magnetism? Watch the video on You. Tube using the link above.