Bell work

Magnetism from ElectricityIAN pg 9-7

Electromagnetism Electric current running through wires

produce a magnetic field Electromagnetism is the interaction

between electricity and magnetism Electric current in a wire isn’t a strong

magnet.

Solenoid A solenoid is a current

carrying wire coiled. It is stronger than just a current carrying

wire. To increase it’s magnetic strength

Add more loops of wire Increase the current

Electromagnet An electromagnet is a solenoid with an iron

core. This is the strongest magnet, because the

iron core’s domains align. Can be 110x stronger than a solenoid with the same # of loops.

Increase strength Add loops Increase current Bigger iron core

Magnetic force and Electric current Electric current in a wire creates a

magnetic field that can exert a force on magnets-moving them.

The direction of the magnetic field depends on the direction of the current that is produced.

Also Magnets can move current carrying wires!

Uses of Electromagnets Electromagnetisms are particularly useful because they can be

turned on and off as needed and they are used for heavy lifting. Electromagnets attract objects containing iron only when a

current exists in the wire. When there is no currents in the wire, the electromagnetism is

turned off.

DOORBELL

This is how the doorbell works as the arrows show the steps from the previous slide.

Electric Motor An electric motor is a device that converts

electrical energy into kinetic energy. All electric motors have an armature-a loop or

coil that can rotate. This is placed in between a permeate magnet

or electromagnet. In motors that have direct current a device

called a commutator is attached to the armature to reverse the direction of the electric current in a wire.

Electric motor continued…..

A commutator is a ring that is split in half and connected to the ends of the armature.

Electric current enters the armature through brushes that touch the commutator.

Every time the armature and the commutator make a half-turn, the direction of the current reverses.

Magnet labYou will need a sheet of notebook paper

Pg 3-4 in Lab book Use the stick, string, magnets and cup. See what they can do. Make sure you can untie knots! Return all supplies to their original

condition.

Put all supplies back into the cup! What did you discover? How can magnets be used? Draw 3 pictures of what you did.

Pg 7-9 Keep the washers in the trays until you

use them. Use one magnet. How many did it hold?

Draw it on your graph. Use 2 magnets How many? Graph it. Use 3 magnets-How many? Graph it. Use 4 magnets-How many? Graph it.

Put all supplies back into the tray! Write down how many washers each #

of magnets held. Look at your graph…how many do you

think 6 magnets will hold? 12 magnets? Why do you think this?