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Properties of magnets

Properties of magnets. Magnets: material or object that makes a magnetic field. Poles- all magnets have 2 - North and south exert forces on magnets or other magnetic materials, like iron and steel. At this pt. all magnets are dipoles(2 poles), and no monopole(1 pole) exists ! .

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Properties of magnets

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  1. Properties of magnets • Magnets: material or object that makes a magnetic field. • Poles- all magnets have 2- North and south • exert forceson magnets or other magnetic materials, like iron and steel. At this pt. all magnets are dipoles(2 poles), and no monopole(1 pole) exists !

  2. MAGNETIC FIELD: area around a magnet that exerts a force. ( a force field) • Magnetic field lines– represent the mag. Field, and always go from N pole towards the S pole. • The closer the lines, the stronger the force.

  3. 2 types of Forces with magnets : Force of Repulsion- like poles with likepoles… ex: (N,N, S,S): theyrepel. Force of Attraction-unlike Poles with unlike poles-- ex: ( N and S) –they attract

  4. Lets draw the magnetic field lines.

  5. Brainpop on magnetism • http://www.brainpop.com/science/motionsforcesandtime/magnetism/

  6. Magnets can exert their forces even thru insulating materials like wood, plastic, and glass if they are strong enough. Conducting materials like iron and steel can block or change the mag. forces.

  7. Permanent magnets- keep their magnetic properties- bar, horseshoe, round..called “hard magnets.”- ferromagnets: “ferro” means: __________. These are the strongest magnets, made of Iron, Nickel or cobalt

  8. Temporary magnets- • lose their magnetism easily. • Called “soft magnets”

  9. Magnetic domains ( Present on all sides )

  10. Magnetic domains- millions of atoms align themselves with other atoms in groups all facing in the same direction. • If a magnet is near a paperclip, the domains in the paperclip will realign with the magnet until the magnet is removed.

  11. USES OF MAGNETS: • junkyards, weather stripping on doors, zippers, latches, cabinet and fridge doors, handbags, etc. compasses, electric motors, microwave ovens, coin-operated vending machines, light meters for photography, automobile horns, televisions, loudspeakers, and tape recorders. A simple refrigerator note holder and a complex medical magnetic resonance imaging device both utilize magnets.

  12. Some materials, like lead and diamonds are not magnetic at all, whereas aluminum can be a weak magnet, but is often nonmagnetic, b/c the atoms are not aligned naturally.

  13. What destroys magnets? • Increasing temperature can ruin the domains ( adding heat ) • Dropping the magnets • Changing the domains alignment Compass needles: • As early as 500 B.C., people were using Lodestone(magnetite) as a compass.

  14. Law of magnetism: LIKE POLES REPEL; UNLIKE POLES ATTRACT http://www.youtube.com/watch?v=2QiyiWLm2FY

  15. INTERESTING FACTS: • GAUSS-unit to measure the strength of a mag. Field. • Mag. Field of Earth is weak compared to a classroom magnet. • The poles of our Earth have reversed about every 500,000 yrs. Last one was about 750,000 yrs. Ago, so we are due!! • Location of our mag. Poles is always changing.

  16. Lab on magnetic field using a compass

  17. Use for observations questions # 1 and # 2

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