Electricity

Static Electricity

Static Electricity

an electrical charge (imbalance of protons and electrons) that has built up inside an object.

Law of Static Charges

like repel( + +,- -)…..opposites attract (+,-)

3 main ways that electrical charges can be transferred:

1 contact

2 induction

3 conduction

WHat happens when 2 objects come into conatnt with eachother?

When any two objects come in contact with each other, electrons will move from one to the other.  In order to increase the flow of electrons, we can use a rubbing motion.

GEN LEP

gain electron negative……lose electron positive

Grounding

allowing an accumulated charge – or sudden contact charge – to travel safely to the ground. The removal of excess electrons into the earth

WHat is it called when a charge is moving

As soon as the charge is moving, it is no longer “Static” – we are now talking about current electricity

Conductors

Any substances that transfer a charge right through them.  

    Insulators

Any substance in which electrons do not move easily from one atom to another. (impede)

 Induced Charge Separation(charging by induction)

By bringing a charged object close to a neutral object, we can “attract” electrons throughout the neutral object either toward or away from the charged object according to the law of static electricity. NO CONTACT

Electric Discharge

- the rapid transfer of electric charge(electrons) from one object to another.

Lightning

• Part of the cycle of electrons.

• These are removed from the Earth’s surface by several processes such as evaporating water, combustion of fuels and wind.

• These charges accumulate in clouds.

• As clouds pass over tall objects – buildings/mountains – they induce a positive charge into the ground based object.  

• Once the charges have a great enough difference, the electrons will leap from the cloud, passing from air particle to air particle, seeking the path of least resistance – to the ground.

• This path is typically a tall object, but a shorter metallic object will often be just as attractive.

• moisture in the air, or pockets of positive ions dictate the path of the lightning bolt as it seeks the easiest path

• lightning rods is a pointed metal rod  that is attached to the highest part of a building. It protects against lightning from striking and if lightning does strike, they direct the charge through the conductor to the ground.

ENERGY

is defined as the ability to do work.  To make anything happen, we need some type of energy.

What is Current?

(source, load, path, connectors) parts and symbols

Current Electricity

electrons that flow in a path.  In order to flow, there must be a source of electrical energy.

Electrical energy

is the energy that is provided by the flow of electrons in an electrical circuit.

 Electric Cells

An electric cell is a portable device that converts chemical energy into electrical energy.

Primary cells

are electric cells that cannot be recharged because the chemical reactions that produce the flow of electrons are not reversible.

Secondary cells

are electric cells that can be recharged and reused many times before they are recycled.  Electrical energy from a wall outlet can be used to reverse the chemical reactions that take place in a secondary cell.

Fuel cells

a fuel cell is a special kind of electric cell through which a continuous supply of chemicals is pumped as the cell operates. 

Direct current (DC)

a flow of electrons in one direction through an electric circuit

Alternating current (AC)

a flow of electrons that alternates in direction in an electric circuit

Today, most of the energy provided by a wall outlet is produced in electric generating stations. The following are ways humans generate energy:

Hydro-electric generation

Moving water- tidal generation

Thermal generation

Coal generation

Oil/natural gas generation

Radioactive materials generation

Wind generation

Light generation

Electrical Power

Electrical Power- is the rate(number) at which electrical energy is produced or used.  

-unit of measurement is the watt (W) 

(one watt is the equivalent of one joule per second(J/s))

-the higher the wattage (power rating value) the more electrical energy a device produces

circuit diagram

A circuit diagram is a way of drawing an electric circuit using standard symbols.

Series

Cells – light was brighter……why more voltage…….why…one direct path….cumulative voltage (voltage is combined) but does not last as long…too much will cause the bulb to burn out….If we have one faulty cell in series we lose power because….path is interrupted…

Loads-

less intense as we increase load (light bulbs)….why…current is being shared by more than one load….so we have less to be used by each bulb. If one light bulb is faulty… lights are out. Example in your life…so damn frustrating….Christmas tree lights… all lights go out

Parallel

light was less bright…..why…less voltage….why….multiple paths…..non-cumulate voltage(voltage is not combined) but will last longer…voltage stays constant so the bulb will not burn out….If we have 1 faulty cell in parallel the electrons use a different path and there is no disruption to the circuit( we still see light)

Loads

equal intensity…multiple paths…if one light bulb is faulty….other bulb gets brighter..

Electric Current  

measured in amps(amperes(A)) by an ammeter 

- represented by “I”--- I Amp Canadian

- measures the volume or number of electrons moving through the circuit

- always the same everywhere in the circuit because electrons have only one path to follow

Amps = amount of electrons flowing through a circuit

Voltage

- measured in volts (V) by a voltmeter

- represented by “V”

- is determined by the difference in the number of electrons from one end of the circuit to the other.  The greater the difference, the stronger the energy of the circuit.

- energy potential of each load (light bulb, motor etc) adds up to the potential of battery

Volts = how much force the electrons are moving with(potential energy or difference in charge between the two ends)

Resistance

- measured in units called ohms (Ώ)   1 Ώ= 1V

          1A

- represented by “R”

- measures how much energy the load uses.

- a load uses some of the electron energy and changes it into different forms of energy(light, heat, mechanical etc) in a process called resistance

- resistance is the ability to change electrical energy into different forms of energy (heat and light)

Resistance formula

 volt divided by current

Current formula

volt divided by resistance

Volt formula

Resistance multiplied by CUrrent