1. Electricity
Mrs. “” Burge

2. Electricity
a form of energy resulting from the existence of charged particles (such as electrons or protons)
either statically as an accumulation of charge
or dynamically (changing/moving) as a current.

3. Electrical charge Measured in coulombs (C)
There are 6.3 * 1018 protons in 1 C of electrical charge
There are 6.3 * 1018 protons in - 1 C of electrical charge

4. Electricity The electrons are transferred, NOT the protons
Unlike charges attract each other, like charges repel each other
Particles with no charge are not attracted or repelled
Force between the charges depends on the amount of charge and the distance between them

5. Electricity
Electrical conductors – materials that allow electrons to move easily through
Metals
Electrical insulators – materials that do not allow electrons to move easily through
Rubber coating on wires, plastic
Electrical resistors – lets some electrons go through but not all – weaker connection
Metalliods, air

6. Electricity 2 types of electricity are: Static electricity
Current electricity

7. Charging
Charging by contact – process of transferring charge (electrons) by touch
Shoe to carpet example
Charging by induction – the rearrangement of electrons on a neutral object caused by a nearby charged object
Hair standing when you hold a balloon by it

8. Static Electricity
Static electricity occurs when there is an excess of electrical charge on an object
Moving some electricity very quickly
Ex. Rubbing shoes on carpet – the electrons jump from the carpet to your shoes and therefore your shoes have an excess of negative charge and the carpet has an excess of positive charge

10. Static Electricity
Static discharge – transfer of charge between 2 object because of a build up of static electricity

11. Lightning

12. Lightning Why does lightning produce thunder?
Sound waves are produced because the electrical energy in a lightning bolt rips electrons off of atoms in the atmosphere and produces great amounts of heat (plasma pockets)
The surrounding air temperature can rise to 30,000 degree Celsius (several times hotter than the suns surface – which is 5, 505 degrees Celsius)
This heat causes the air to rapidly expand producing the sound you hear as thunder
We use lightning rods to control the static build up from causing more damage – the rod creates a path to earth to prevent damage to the building

13. Static Electricity Why does your hair get static-y when you brush it?
The electrons from the brush jump to your hair causing it to either:
Repel the other negative charge on your head – and stand up away from your head
Attract the positive charge on your head and stick to your face

14. Static Electricity
Why do clothes stick together when you get them out of the dryer?
Static electricity
When the clothes hit each other in the dryer they pass electrons, some clothes gain electrons and make them attracted to the clothes who have lost electrons
Dryer sheets contain positively charged materials to help fight static cling!

15. Law of Conservation of Charge
Charge can be transferred from object to object but cannot be created or destroyed
Example: when you rubbed your shoes on the carpet, the electrons transfer from the carpet to your shoes, but there is still the same amount of electrical charge

16. Electric Fields
An electric field surrounds every electric charge and exerts the force that causes other electric charges to be attracted or repelled
To make things confusing, in most diagrams the electric fields are usually shown with arrows saying what protons would so
So just remember that Electrons do the Opposite!

17. Current Electricity
Electric current is the net movement of electric charges in a single direction - it is measured in Amperes (amps)
One amp is equal to one coulomb of electric charge flowing past a point every second

18. Current Electricity
Electrons are always moving in different directions
When an electrical current runs through the object the electrons are still moving randomly but drift with the direction of the current
Example - ball bouncing down a stair case – the ball will bounce in random directions but it continues to go downstairs
Water moving down a pipe
First graders moving to the lunch room

19. Current Electricity
Electric current moves from low voltage to high voltage
Voltage difference is related to force that causes electric charges to flow – measured in volts
There needs to be a voltage difference for electrons to keep flowing
Positive charge does not flow, the negative electrons are the ones that actually move in a circuit
Because diagrams follow the positive charge (which doesn’t actually move) it is always the opposite, so voltage and flow with be opposite of either other

20. Current Electricity
Dry cell batteries – consists of 2 electrodes surrounded by material called electrolyte (which enables charges to move from one electrode to the other
Wet cell battery – 2 connected plates made of different material – electrolyte is a liquid in this type of battery

21. Circuits
Electric current – needs closed path that electricity current follows
Series Circuit – electric circuit with only one branch
Open circuit – when there is a disconnect between the elements and the electricity cannot complete the circuit
Parallel circuit – contain 2 or more branches (can be turned on and off separately)

22. Electricity
Resistors cause some of the electricity to transfer to the resistor itself to protect more delicate electronics
resistance is the tendency for a material to resist flow of electrons and to convert electrical energy into other forms of energy (thermal)
resistance is measured in ohms Ω

23. Electricity
In your house we use fuses and circuit breakers to control the currents
Fuses are a glass cased small piece of metal that melts if the current becomes too high
Circuit breakers have switches that are automatically switched off when the current gets too high to prevent fires

24. Ohm’s LAW
Voltage difference, current and resistance in a circuit are all related by Ohm’s law

25. Ac vs DC AC – Alternating current – household electrical outlets
The electrons change direction so many times a second
Helpful if being shocked because it changes directions and allows you to get away from it
DC – direct current – battery powered devices
The electrons do not ever change directions
Can be extremely bad if getting shocked by something with a lot of voltage like a car battery