1. Magnetism and electricity

2. Electric current Magnetism is caused by a moving charge
Electric current is moving charge
Current moving through a wire produces a magnetic field
This is how a circuit breaker works
As the current increases (closer to being an overloaded wire) the magnetic field increases
When the magnetic field is strong enough it flips the switch (w/ a permanent magnet in it), opening the circuit.

3. Circuit Breaker Circuit breaker switch (magnet)
wire
Too much current creates a magnetic field strong
enough to flip the switch and break the circuit

4. Right hand rule
You can determine where the magnetic field will be by the right hand rule.
Place your thumb on a wire carrying current pointing your thumb in the direction the current is going (use your imagination don’t shock yourself)
Wrap your fingers around the wire and your fingers will point in the direction of the magnetic North field (not geographic North), the opposite is South

5. Right Hand Rule
Actual wire with a current surrounded by iron filings

6. To increase this effect…
Coil the wire into loops forming a cylinder
this coil is called a solenoid
The magnetic fields bunch up inside the loops overlapping each other.
When a current is run through the wire an electromagnet is created.
Place a ferromagnetic material (one that can be magnetized) in the loop to increase the effect.

7. Magnetic Field in a Coil
If you keep adding loops on top of one another you get a stronger magnetic field

8. Electromagnet
Electromagnet is a magnet that can be turned on with current running through and then turned off.

9. Electric (Door) Bell
When the current is on, magnetic force pulls hammer to hit the bell
No current, no magnetic field. The springs push everything back.
But is also attracts this break point which opens the circuit
Break point is released, current resumes…

10. homework Pg
10-13; 15; 21-27