magnetism. observe: snsn attract or repel? observe: snsn attract or repel?

Magnetism

Observe:

SN SN

Attract or repel?

Observe:

S N SN

Attract or repel?

Observe:

S N

SN

Attract or repel?

Observe:

SN

SN

Attract or repel?

Observe:

SN

SN

Make a map of the magnetic field around the

bar magnet

N S

Make a map of the magnetic field around the horseshoe magnet

Try this.

Try this.

What does the current in the wire do?

The magnetic field, B

N SB

A current makes a magnetic field

I

B

A current makes a magnetic field

I

B

I

BThis is called the right hand rule

Fields

• If you put a ______ in a __________ field, it will experience a force.

Fields

• If you put a ______ in a __________ field, it will experience a force.

• If you put a mass in a gravitational field, it will experience a force.

Fields

• If you put a ______ in a __________ field, it will experience a force.

• If you put a mass in a gravitational field, it will experience a force.

• If you put a charge in an electrical field, it will experience a force.

Fields

• If you put a ______ in a __________ field, it will experience a force.

• If you put a mass in a gravitational field, it will experience a force.

• If you put a charge in an electrical field, it will experience a force.

• If you put a magnet in a magnetic field, it will experience a force.

Oddly enough…

Electrical and magnetic fields can attract and repel.

Gravitational fields seem to only attract

The relationship between electricity and magnetism

A moving charge affects a magnet

A moving magnet affects a charge

The relationship between electricity and magnetism

A moving charge affects a magnet… it makes a magnetic field

A moving magnet affects a charge… it makes an electrical field

The relationship between electricity and magnetism

A moving charge affects a magnet… it makes a magnetic field

A moving magnet affects a charge… it makes an electrical field

There is an application of the right hand rule for each of these

The relationship between electricity and magnetism

A stable magnetic field affects a charge…

A stable electrical field affects a magnet…

The relationship between electricity and magnetism

A stable magnetic field affects a charge…… only if the charge is moving

A stable electrical field affects a magnet… …only if the magnet is moving

The relationship between electricity and magnetism

A stable magnetic field affects a charge…… only if the charge is moving

A stable electrical field affects a magnet… …only if the magnet is moving

There is an application of the right hand rule for each of these

Electromagnets

• A coil of wire, carrying a current makes a magnetic field.

• If you put the coil around a piece of iron or steel, it becomes an electromagnet.

Electromagnets

• A coil of wire, carrying a current makes a magnetic field.

• If you put the coil around a piece of iron or steel, it becomes an electromagnet.

Where could you use an

electromagnet?

Solenoid

If a magnet can move into and out of the coil, it is called a solenoid.

Solenoid

If a magnet can move into and out of the coil, it is called a solenoid.

Where could you use a solenoid?

Electric motors

• An electric motor converts electrical energy into work, usually rotational motion.

• Usually, a magnet makes coil of wire rotate when a current is flowing.

Which direction is the force on the wire?

Which direction is the force on the wire?

Use the right hand rule !

B = the magnetic field =index finger

I = the (+) current=thumb

F = force on the wire =palm

B = the magnetic field =index finger

I = the (+) current=thumb

F = force on the wire =palm

What is the missing vector ?

I

B

What is the missing vector ?

I

B

Motors--Convert electrical energy into mechanical energy--An electric current causes a coil of wire to spin in a magnetic field--The rotational motion can do many jobs

Mechanical Energy Electrical Energy

Generators--Convert mechanical energy into electrical energy--A coil of wire spinning in a magnetic field causes an electric current--There are many ways to spin the generator

Mechanical Energy Electrical Energy

Motors--Convert electrical energy into mechanical energy--An electric current causes a coil of wire to spin in a magnetic field--The rotational motion can do many jobs

Generators--Convert mechanical energy into electrical energy--A coil of wire spinning in a magnetic field causes an electric current--There are many ways to spin the generator

Mechanical Energy Electrical Energy

12

34

56

Generator: If you move the wire, the force is exerted on the charge

Motor: If you move the charge (a current), the force is exerted on the wire

B B

I

Force EMF

Mechanical Energy Electrical Energy

B = the magnetic field =index finger

v = velocity of moving wire

=thumb

EMF = force on the charge =palm

What is the missing vector ?

v

B

What is the missing vector ?

v

B

What is the missing vector ?

v

EMF