1. Chapter 8 Electricity, Magnetism and its uses
General Properties of Magnets
Magnetism: comes from the region in Greece called
Magnesia that contained certain rocks called
lodestones that produced forces between each
other.
They were stones that contained iron ore called magnetite.
The Chinese used them early in the 12th century to navigate their ships

2. Magnetic Poles
Like electric charges magnetic poles produce forces that are broken down into north and south seeking poles.
The strength of their interaction depends on the distance between the poles.
Like poles repel and opposites attract.

3. Magnetic Field
The magnetic field is the space around the magnet in which the force is exerted and is represented by field lines (just like electric field lines).

4. Lines go from north to south so arrows will always point away from north and toward south

5. Magnetic domains
A microscopic cluster of atoms with their magnetic fields aligned.
Made up of billions of atoms that are aligned either to the north or south pole.
Their strength is represented by arrows and the number and alignment of arrows shows the strength of the magnet.

6. Magnetic Materials
Iron, cobalt, and nickel are magnetic elements because their atoms behave like magnets.
Common definition of magnetism is the ability to attract iron.
Steel is magnetic because it is an alloy that contains iron.

7. Random and aligned arrangements of domains.

8. Electromagnetism
Electromagnetism is magnetism produced by electric charge in motion.
Electromagnetic induction is the production of a magnetic force in a conducting circuit by changing the strength, position, or orientation of an external magnetic field.
This can be done by using a coil of wire wrapped around a moving magnetic object.
The more coils of wire, the stronger the magnetic field will be and more voltage will be produced.

9. Electromagnetism
Faraday’s Law states that the induced voltage in a coil is proportional to the product of the number of loops and the rate at which the magnetic field changes within those loops. (how fast the magnet is moving inside the coils).

10. Electromagnetic Induction
is the process of producing an electric current by moving a loop of wire through a magnetic field
A galvanometer is an instrument that uses an electromagnet to measure electric current

11. Current
AC current (alternating current) can reverse the direction of the flow while keeping in a regular pattern
DC current (direct current) can not change directions; will flow only in one direction
The strongest magnetic forces are located at the magnetic poles
Current that flows in an electric circuit carries electrical energy
A switch that reverses the direction of the current in a motor is a commutator

12. Generators, Motors, and Transformers
The function of an electric motor is to convert electrical energy to mechanical energy
The function of a generator is to change mechanical energy to electrical energy
transformers can be a step up transformer or a step down transformer

13. step up transformers The step up transformer increases voltage
Ex. A step-up transformer the number of turns of wire is greater in the secondary coil than in the primary coil, and the output voltage exceeds the input voltage

14. Alternative Energy
Hydroelectricity is electricity generated by falling water
Water that flows due to the gravitational forces among Earth, the Moon, and the Sun has tidal energy
Devices that use semiconductors to produce electricity from solar energy are photovoltaic cells

15. Fossil Fuels Three types of Fossil Fuels Petroleum Natural gas Coal
Coal is the type of fossil fuel that is formed from the remains of fernlike plants
Petroleum is separated into different compounds due to fractional distillation

16. Fossil Fuels
Natural Gas produces fewer pollutants than other fossil fuels
Petroleum is make of hydrocarbons
Coal contains more impurities than other fossil fuels
One of the major reasons for alternative fuels is that fossil fuels are being used at a faster rate than they can form. This is why coal is considered a non renewable source of energy.

17. Biomass fuels
Fuels made from renewable organic matter are referred to as biomass fuels.
Wood
Rice hulls
Corn
Sugar cane

18. Nuclear fuels Fuel generated by nuclear fission
The temperature generated by the nuclear reaction is the biggest challenge in using this type of fuel
The part of a nuclear reactor in which the fuel is located is the core.
In nuclear fusion or in fission matter is converted into energy
The fuel used inn a nuclear reactor usually comes from uranium-238.
The best hope of safe, long term containment of radioactive waste is deep stable rock deposits.