4.3.1 Magnetic Fields and Electromagnetic Induction The Earth’s Shield

All charges produce ELECTRIC FIELDS Moving charges produce MAGNETIC FIELDS –PERPENDICULAR to the motion of the charge Magnetic field lines Electromagnetic Induction

Making a Magnet Magnetism is a FIELD FORCE No contact required All atoms have “some” natural of magnetism Three strongly magnetic elements IRON, NICKEL, COBALT

Magnets produce magnetic fields Moving magnets produce ELECTRIC FIELDS –PERPENDICULAR to motion of the magnet –This causes ELECTRICAL CURRENT to flow Electromagnetic Induction

Magnetic Field Lines Rules for field line directions Outside magnet  NORTH TO SOUTH Inside magnet  SOUTH TO NORTH

Magnetic Field Maps N S

Magnetic Field Maps S N N S

Magnetic Field Maps S N

N S Determine the direction of the magnetic field lines at each point. Where is the field strongest? Example #1 Field is strongest at point C. BACD

Determine the direction of the magnetic field lines at each point. Where is the field strongest? Example #2 Field is strongest at point F. FEGH S N N S

The needle of a compass is a small MAGNET The north pole of a compass needle –… is marked with a small “N” or a prominent color –… points toward magnetic SOUTH poles. Compass

Determine the direction in which the compass will point. Example #3 S N

Convection currents in the outer iron core produce the Earth’s magnetic field The geographic NORTH pole of the Earth acts like the SOUTH pole of a magnet! Earth’s Magnetic Field

The Magnetosphere

End of – PRACTICE