1. Magnetism: What you SHOULD know. What sticks (attracted) to magnets? –Plastic, liquids like water, metals? -Do all metals stick? –No Magnets are picky – iron containing materials (cobalt and nickel too) –But plastics and liquids with iron in them are magnetic too –And what are magnets or permanent magnets used to be iron containing but now exotic Magnets interacting with other magnets –Can attract or repel! –They have POLES North and South -like poles repel, opposite poles attract –All magnets have a north and south pole, break a magnet and the pieces have north an south poles too! –Compass has magnet at the end of a needle and it is attracted to other magnets and the Earth is one BIG magnet. Magnetic Patterns or Fields –Lines of Force (called field lines) trace out the direction a small magnet would point –Can use iron filings to show these Lines of Force (field lines) –they start and end on the magnet! –The Earth’s north pole is actually a magnetic South pole!! –Magnetism goes through (penetrates) non-magnetic material. Electricity makes a magnetic field –Many loops (a coil) around a nail can make a strong electro-magnet –Information (music) can be stored using electricity to make permanent magnets on a tape Magnets can make electricity –Move a magnet in a coil and current is generated –Generator motion makes electricity/ Motor electricity makes motion

2. Magnetism: What you DON’T know. – fun with strong magnets Actually magnets can effect more than just iron containing material! Magnets with all metals – Eddy current –A moving magnet (1) makes a current in a stationary metal, but current makes a magnet (2)! And magnets interact! –Interaction acts to slow (damp) the magnet. Magnets weakly attract nearly all non-iron containing materials – PARA- magnetism –Always attractive –Oxygen, O 2, (even liquid oxygen) is paramagnetic. Magnets very weakly repel a small number of materials – DIA-magnetism –Always repel and this can make levitation!! –Materials include graphite (aka pencil lead); water (frogs and strawberries too). –The effect is particularly strong in superconductors! –And this can be made to levitate a train!! Other fun levitation schemes. –Active control –Mechanical constraint

3. Magnetism: What you SHOULD know. (I) What sticks (attracted) to magnets? –Plastic, liquids like water, metals? -Do all metals stick? –No Magnets are picky – iron containing materials (cobalt and nickel too) –But plastics and liquids with iron in them are magnetic too –And what are magnets or permanent magnets used to be iron containing but now exotic Magnets interacting with other magnets –Can attract or repel! –They have POLES North and South -like poles repel, opposite poles attract –All magnets have a north and south pole, break a magnet and the pieces have north an south poles too! –Compass has magnet at the end of a needle and it is attracted to other magnets and the Earth is one BIG magnet. Dip the magnet into a bucket of different objects - What sticks? –Coins, plastic, wood, nails, water, etc. Show plastic magnets and ferrofluid. Show neat magnets, balls, super strong, refrigerator etc. Show repulsion attraction. –Break a magnet and show they always have a north and south. –Play with a compass.

4. Magnetism: What you SHOULD know. (II) Magnetic Patterns or Fields –Lines of Force trace out the direction a small magnet would point –Can use iron filings to show these Lines of Force –Earth’s north pole is actually a magnetic South pole!! –Magnetism goes through material. Electricity makes a magnetic field –A coil around a nail can make a strong electro- magnet –Music can be stored using electricity to make permanent magnets on a tape Magnets can make electricity –Move a magnet in a coil and current is generated –Generator motion makes electricity/ Motor electricity makes motion. Magnetic Patterns or Lines of Force or Fields –Use magnets –Use iron filings –Use 3D demo –Use magnerite Electricity makes a magnetic field –Field pattern near wire or loop –Show electromagnet Magnets can make electricity –Move magnet near wire or coil. –Show handcrank generator

5. Magnetism: What you DON’T know. (I) – fun with strong magnets Actually magnets can effect more than just iron containing material! Magnets with all metals – Eddy current –A moving magnet (1) makes a current in a stationary metal, but current makes a magnet (2)! And magnets interact! –Interaction acts to slow (damp) the magnet. Magnets weakly attract nearly all non-iron containing materials – PARA-magnetism –Always attractive –Oxygen, O 2, (even liquid oxygen) is paramagnetic. Eddy Current –Magnetic/ non magnetic ball bearing down a metal/plastic tube. –Move magnet over a copper plate. Magnets weakly attract PARA- magnetism –Aluminum bar on a string with strong magnets on a turntable –Liquid O2 dripped on strong magnet.

6. Magnetism: What you DON’T know. (I) – fun with strong magnets Magnets very weakly repel a small number of materials – DIA- magnetism –Always repel and this can make levitation!! –Materials include graphite (aka pencil lead); water (frogs and strawberries too). –The effect is particularly strong in superconductors! –And this can be made to levitate a train!! Other fun levitation schemes. –Active control –Mechanical constraint Magnets very weakly DIA-magnetism –Always repel and can levitate –Materials include graphite (aka pencil lead); water (frogs and strawberries too). –The effect is particularly strong in superconductors! –And this can be made to levitate a train!! Other fun levitation schemes. –Active control –Mechanical constraint

7. Magnetism: What you DON’T know. (I) – fun with strong magnets Magnets very weakly repel a small number of materials – DIA-magnetism –Always repel and this can make levitation!! –Materials include graphite (aka pencil lead); water (frogs and strawberries too). –The effect is particularly strong in superconductors! –And this can be made to levitate a train!! Other fun levitation schemes. –Active control –Mechanical constraint Magnets very weakly DIA- magnetism Eddy Current –Magnetic/ non magnetic ball bearing down a metal/plastic tube. –Move magnet over a copper plate. Magnets weakly attract PARA- magnetism –Aluminum bar on a string with strong magnets on a turntable –Liquid O2 dripped on strong magnet.