Magnetic properties

Naturally magnetic elements Why is the Earth magnetic? How do magnets interact with each other? How are magnets created? What happens to magnets over time?

Field Lines Imaginary north pole. These are similar to electric field lines. Imagine the force experienced by a tiny north pole, that is the direction of the field. Draw the lines for the following. NN NS SS

Electromagnetism Oersted discovered ___________________ __________________________________. There is a predictable nature of the magnetic field created by a current. First right hand: What is the direction of the magnetic field created by a current carrying wire? Describe: HW 1-3 p560

Given current predict field

Magnetic field created by a current carrying loop. 2 nd Right hand rule For a current carrying loop_______________ ____________________________________. Your thumb will point in the direction of the _____________________ How do you make an electromagnet? HW 4-6 p. 563

Magnetic field created by a current carrying loop. 2 nd Right hand rule

Electromagnetic interaction Data storage: Magnetic Domains: Switching poles and dating the Earth: Evidence for tectonic plate movement. Effect of magnetic fields on electromagnetic radiation. Refraction. Importance to the life on Earth

Forces caused by magnetic fields Force on a current carrying wire. If a wire carrying a current passes through an existing magnetic field it will _________________. This force can cause the wire to _________. How do you predict the direction of the force? Describe: HW 28,29,30,32 pp

3 rd right hand rule

Force on two parallel wires Which one attracts? Same directionopposite directions

Force on a wire in a loop. The portion of the loop that cuts the magnetic field experiences _____________. That force follows the 3 rd right hand rule. So as one side of the loop is being pushed up the other side where the current is reversed is being pushed down. This causes a ______________________. Once the loop has rotated to a vertical position ___________________________ ___________________________________.

Examine the loop Hooray Faraday!! Which way is the current moving?

Uses of this phenomena Devices Loud speakers Hearing aides Is the current always the same? Is it always moving in the same direction? Does it need a piece of metal in the loop? Why does the diaphragm move?.

More uses Measuring current Galvanometers (ammeters) What is the purpose of the red loop in the center? As the current changes so does the force.

Electric motor: ___________ to mechanical Electric motors, name as many as you can. HW what is the function of the Armature and the commutator?

Generator: _____________ to electric energy Generators (Name some) Alt. energy sources How many ways do we generate electricity?