Warm-Up What equation do we get from Ohm’s Law? What is the equation for electrical power?

Worksheet Ohm’s Law & Power Practice Problems You will have 40 minutes to work on these problems. If you do not finish, it will be hw.

What is a magnet? Describe in your own words what a magnet is.

What is Magnetism? Force of attraction or repulsion due to electron arrangement Magnetic forces are the strongest at the poles Magnets have two poles: North and South

Magnetic Poles and Fields Magnets always have two poles If a magnet is cut it will still have two poles Why do you think this is? Like magnetic poles repel Unlike magnetic poles attract A magnetic field is the area in which magnetic forces act

Earth’s Magnetic Properties Gilbert was a scientist that showed that the Earth behaves as a magnet The Earth’s magnetic field is strongest at the poles Earth’s magnetic field is called the magnetosphere

Compasses Compasses are used to determine direction How do compasses help us determine direction? Compass needles are magnetized and respond to the magnetic field of the Earth Compasses point to the MAGNETIC POLES OF THE EARTH

Electromagnetism Discovered by Oersted (scientist) Relationship between electricity and magnetism

What is an Electromagnet? Electromagnet – a magnet made from a current bearing coil of wire wrapped around an iron or steel core.

Increasing the Strength of Electromagnets Increase the voltage or current Increase the number of loops of wire

What is a Generator? Generator – a machine that changes mechanical energy to electrical energy It moves a magnet near a wire to create a steady flow of electrons. This creates currents in coils of wire.  The action that forces this movement varies greatly, ranging from hand cranks and steam engines to nuclear fission, but the principle remains the same.

Recall the bike… Explain how peddling the bike produced the current to light the light bulbs?

What is a Motor? Motor – a device that changes electrical energy to mechanical energy that can do work. Why would this be useful?

Electric Motors vs. Generators Electric motors convert electricity to mechanical energy in order to do work Generators convert mechanical energy to electrical energy

That’s All Folks !!!! Begin working on your FINAL EXAM REVIEW. REMEMBER: All missing work and corrections are due Friday, May 16th