MAGNATISM

A magnet is a piece of metal that can attract other metallic things such as steel, nickel, and cobalt.

The name comes from magnetis lithos.

Lodestones or magnetites are natural magnets.

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​Magnets

Magnets have two poles - the north pole, and the south pole.

Magnets attract other magnets and metals.

When opposite poles are pointed toward each other, they attract.

When same poles are pointed to each other, they repel.

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​Magnets

​Key Concepts 4- Magnetism

The force that magnets exert is called magnetism.

Magnetism is caused by the magnetic field which is invisible.

The magnetic field is formed around the magnet.

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Magnetism

Some materials are nonmagnetic like cloth and plastic.

Materials with iron, nickel, and cobalt can become magnets.

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Magnetic Materials

​Magnetic Fields:​

All magnets are surrounded by a magnetic field. A magnetic field is defined as: The region around a magnet where a force acts on another magnet or on a magnetic material

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Magnetic field lines are used to represent the strength and direction of a magnetic field.

​Magnetic Forces

Remember this​!

The Magnetic field always comes out of the north pole to the south pole.​

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Magnetic Field

• Around a magnet is a magnetic field (B-field)

  • At every point in space there is a magnetic force

  • Earth's magnetic field can be visialized with a compass

  • Unit for magnetic field: Tesla (T)

• Magnets can be visualized with field lines​.

  • Start at N pole and ends at S pole

  • More lines in one area means a stronger field. ​

Magnetic Field

• Since current (moving charges) make B-fields, then other B-fields apply a force to moving charges

• For a moving charge to experience a force:

  • Charge must be moving

  • The velocity of the charge must have a component perpendicular to the magnatic-field​