P7 Magnetism & Electromagnetism

Magnets exert forces on each other

- like poles repel, and unlike poles attract (north/south poles)

- The area around a magnet where it can exert a farice its its magnetic field.  The magnetic field lines of a bar magnet curve around from the north pole of the bar magnet to the south pole.  The magentic field is strongest at its poles

- The needle of a compass is a tiny bar amgnet.  It point sin the direction of any magnetic field.  When not near a magnet a compass will point north. because its direction of teh Earth's magnetic field

- Iron, steel & nickel are all magnetic materials. Steel is used instead of iron to make permanent magnets because steel does not lose its magnetism easily, but iron does

-Permanent magnets creat their own magnetic field.  

- induced magnetism is magnetism created in an unmagnetised magnetic material when the material is placed in the magnetic fiel

An magnetic field is also found around a wre that has a current passing through it

-the magnetic feidl is made up of circles areound the wire.  Swopping the direction of the current reverses the direction of the magnetic field

- electromagnets are used in scrapyard cranes, circuit breakers, electric bells and relays

- an electromgnet works in a circuit breaker or electric bell or a relay by attracting an iron armature which opens a switch