1. Electricity and Magnetism
CHAPTER 13
Electricity and Magnetism

2. Electric Charges Atoms are the tiny building blocks of everything
Almost all atoms have 3 different particles
Positive charge (+)
Negative charge (-)
No charge
Matter has the same amount of positive as negative

3. Static Electricity
Charged particles move between objects that are close to each other
Static electricity – happens when positive and negative charges no longer balance
Static means “not moving”
Moving charges create electricity
They also change into sound, light, and heat energy

5. Storm Clouds Charged particle move between storm clouds
Positive particles are near the TOP
Negative particles are near the BOTTOM
The static electricity is released as Lightning
Lightning also creates a mighty sound – thunder

7. How Charged Objects Behave
You can PREDICT this
If two objects have opposite charges (+ & -) they will pull to each other
Electric force – is the pull or push between objects that have a different charge
A charged object can attract something that has no charge
If two objects have same charges (+ & +) they will push away from each other

8. (+) (-) PULL
(-) (+) PULL
(+) (+) PUSH
(-) (-) PUSH

9. + + + -

10. An Electric Field
Electric field – the space around electrically charged objects
It is invisible
But scientist will draw lines to represent it
Strongest closest to the object and get weaker as it moves away
A POSITIVE electric field attracts NEGATIVE charges and pushes away POSITIVE

12. How Electric Charges Move
Electric current– electric charge in motion
They flow from one place to another
It travels QUICKLY and INVISIBILY
The flow of electric charge is not the same in all materials

13. Insulators DO NOT CHARGE EASILY Electric charges move SLOWLY Plastic
Rubber
Glass
Dry wood

14. Conductors CHARGED MORE EASILY MOVE QUICKLY Copper Wire Silver
Most metals

16. Closed Circuit Circuit – a loop where electric travels
DOES NOT HAVE ANY BREAKS

17. Open Circuit
Has opening or breaks where the electricity will stop following
MOVE SLOWLY
Resistance – means the material does not allow electric charges to flow through it easily – the wire gives off light

18. Types of Circuits
SERIES CIRCUIT – electric charges can flow in only ONE path
Electric charges flow in a single loop
All bulbs receive the same amount of energy
If one bulb “burns out” it acts like an off switch
NOT USED A LOT

20. Types of Circuits
PARALLEL CIRCUITS - has two or more paths for the electric charge to flow
There are little loops on the big loops
Each loop is a separate path for the electric charge
A break DOES NOT shut off the electric of the whole loop, just the small loop
Used in homes, schools, and offices

22. Magnetism
Magnet – anything that attracts other things made of iron, steel, and certain other metals
Magnetism – is a force that acts on moving electric charge and magnetic charges that are near the magnet
Magnet comes from Magnesia (a place in Turkey that was known for its magnetic materials)

23. Magnetic Fields
Magnetic field – invisible field around the magnet, goes out in all directions
Its shape depends on the shape of the magnet
It is STRONGEST at the magnets “pole points”

24. Magnetic Poles All magnets have two poles – NORTH & SOUTH
Opposite poles have opposite charges
Unlike charges attract each other
Like charges repel (push)
IF you break a magnet in two you will then have 2 magnets with 2 poles (4 poles in total)

25. Largest Magnet in the WORLD
Earth behaves like a large magnet
Like a magnet, it has the strongest
pull at its poles
The Earth’s poles are no the same as the geographic poles
The magnetic NORTH pole is in Canada
The magnetic SOUTH pole is near Antarctica

26. How Compasses Work
Compass – a helpful tool that help you find directions
The needle will always point you in the direction of north
If you are near a magnet, the compass will not work correctly

28. Electromagnets Invented by Hans Christian Oersted
Electricity and magnetism are closely related
Both are results of charged particles moving
We use them a lot in our daily lives
Electromagnet – is a coil of wire with many loops through which an electric current passes
To make the field stronger it is wrapper around copper
Can be a VERY POWRFUL MAGNET

29. Uses for Electromagnets
Used in industry to lift heavy materials
Complex machines used by doctors and scientists
Are a part of many electronic gadgets:
Televisions
Fans
DVD players
Doorbell
A motor
Earphones

30. Electrical Energy This helped make electric, motors, and generators
The power of magnetism can be transformed into the power of electricity
This helped make electric, motors, and generators
When a magnet is moved, its magnetic field moves with it
Changing a magnetic field generated electricity
More loops = stronger
Faster = stronger

31. A Flashlight without batteries
1831 – Michael Faraday invented a machine that used magnets to transform motion into an electric current
Turning a crank
Used in emergency flashlights and radios

32. Currents
Most homes, school, and businesses today get their electricity from generators
Generator – is a machine that creates electric energy by turning coils of wire around powerful magnets
Uses magnets and wires to turn mechanical energy into electrical energy

33. Pioneers in Electricity
1740s – Benjamin Franklin describe positive or negative
1829/1831 – Joseph Henry and Michael Faraday produce a current by changing a magnetic field
1879 – Thomas Edison created incandescent light bulb

34. How Generators are powered
Many ways for a generator to produce electrical energy
Wind power – a wind turbine changes the energy of the blowing wind into electricity
Hydroelectric Power – the power of falling water is changed into electricity by generators near Niagara Falls

35. Electrical Safety
If you are not careful, electricity can case a serious shock or start a fire
Respect the power of electricity
Read and follow the instructions that come with every electrical produce
Replace worn or cracked electrical product
Relocate, or move, appliance cords so people will not walk on or trip over them, and children or pets can’t pull them