Module II – MAGNETISMObjective:2.1 Distinguish magnetic substances from ferromagnetic, and non- magnetic substances.2.2 Map the magnetic fields of magnetized objects.
History of Magnetism Discovered by the Chinese Used by magicians and sailors Illusions….. MagneticHill, New Brunswick Bermuda Triangle
Categories of Substances Three Categories Magnetic Ferromagnetic Non-magnetic
Magnetic Invisible fields Attract or repel Object that has a field and that can attract some other objects. Example: horseshoe magnet
Not a magnetFerromagnetic Is attracted by a magnet Can be magnetized Must contain iron, nickel or cobalt eg: paper clip or nail
Non-Magnetic Is not attracted by a magnet Example: glass, plastic, or wood
Important Facts about Magnets Facts: All magnets have two poles, a North (N) and a South (S). They are known as dipoles. Fields are infinite in size & 3-Dimensional Similar poles repel & Repulsion opposite poles attract.Important Attraction
ImportantPolesN attracts South Opposites attractS attracts NorthN repels North LikesS repels South repel
Mapping Magnetic Fields Remember Around lines never cross •the a magnet there are lines of •Always force that goes fromstronger the attraction have direction South strength •Closer the lines, North to and (magnetic field).
Compass North The needle of the compass is end magnetic Red Tip of needle is North Important Red Tip will always be attracted towards South Tip of arrow Is North thereforeExample #1 It is attracted to SouthExample #2
Magnetism is a property that makes certain material attract or repel. Ferromagnetic Attracted by magnet Must contain Fe, Ni, Co HINT Nonmagnetic Nerd Not attracted by magnet to Sexy Opposites attract (i.e N & S) Likes Repel (i.e. S & S or N & N) Magnetic Field Arrows always go from north to south (outside magnet) Lines of force never cross The closer the lines, the stronger the field Compass Red portion of compass needle is North and is always attracted to South