Zusammenfassung der Ressource
magnets and electromagnets
- bar magnets
- permanent magnets
- magnets are made from magnetic material.these are
metals that can be magnetised or will be attracted to
a magnet.most materials are not magnetic,but
iron,cobalt,nickel and steel are.
- attract and repel
- if you bring 2 magnets together 2 things can happen-attract or repel.
- magnetic fields
- magnets create magnetic fields.these cant be seen.they fill the space
around a magnet where the magnetic forces work,where they can attract
or repel
- although we cannot see them,we can
detect them with iron filings.the tiny pieces
of iron line up in a magnetic field.
- electromagnets
- when an electric current flows in a wire it creates a magnetic field around the wire.by
winding the wire into a coil we can srengthen the magnetic field.electrommagnets are made
from coils like this.we can strengthen the electromagnet wrapping the coil around a iron
core.-adding more turns to the coil.-increasing the current.
- magnetic field
- the magnetic field of an electromagnet is like a bar
magnet one however it can change direction
- unlike bar magnets that are permanent magnets,electromagnets can be
turned o and off by closing or opening the switch.
- electric bells
- electric bells have an electromagnet.
- 1)the current flows through the circuit,the electromagnet
makes a magnetic field.
- 2)electromagnet attracts the springly metal arm.
- 3)the arm hits the gong,which makes a sound.
- 4)the circuit is broken.the arm is out of position.
- 5)electromagnet turned off and the springly metal arm moves back.
- 6) the circuit is complete again.