ELECTRICITY
Jan 19, 2016
ELECTRICITY
What would life be like without electricity?
Maybe like this…
Or this…
You couldn’t do this…
Or this…
And our cities wouldn’t look like this…
Why is electricity important to us?
Electricity provides us with … Heat Light Sound Motion
So where does this “magic” electricity you use every day come
from?
Abracadabra!
Electron movement!
SO, WHY DO ELECTRONS MOVE?
Let’s Review First
Electrons are the only particle of an atom that can move from one atom to another
Electrons have a negative charge, protons have a positive charge
Everything in environment carries either a positive, negative, or neutral charge Add electrons and an atom becomes more
negatively charged Take away electrons and an atom becomes
more positively charged Charged atoms are called IONS
Movement of Electricity
Electrons will move when they have a “push” of energy from A Battery A Power Plant or other Energy Source
The energy is then transferred through a conductive material, usually wires or cables, this flow of electrons (negative charges) is called an electrical current
Electrical Currents
Electrons flow from areas of negative charge to areas with a positive charge in a current
If the current runs in a circular path from the battery or power source it is called a circuit
What materials can carry electrical currents?
Conductors-electrons flow easily through them Examples: metals such as copper, gold, silver
Semi-Conductors-electrons move less easily through them Examples: aluminum, zinc, silicon
Insulators-electrons DO NOT flow easily through them Examples: rubber, paper, plastic, wood
Electrons Have Mass Ever notice that your phone becomes
warm when you are using it, or a plug in an outlet feels warm when you remove it?
This is because electrons have MASS, it is extremely small, but enough so that when electrons are flowing some of them bump into each other, creating HEAT
WARNING: The safest way to charge electronics is to turn them off while they are charging, otherwise you could start a FIRE!
More Electric Safety
Don’t over connect outlets!
State Farm Holiday Safety Video
How do power stations make energy to create electricity?
Usually burn fuel which heats water and creates steam
Steam turns turbine which turns a rod with a magnet
Causes electrons to flow around a wire wrapped around the magnet
Electrons then carried by wires throughout the region
How is Electricity Transported?
How do batteries work?
Batteries use energy stored in chemicals to allow electric current to flow
Once the energy is used up, the current can no longer flow
The current will flow from the negative end of the battery to the positive endNegative end-ANODEPositive end-CATHODE
Static Electricity Called “non-moving” electricity Created when there is a build up of
electrons on one object and they try to neutralize with another positively charged object
The charge “jumps” from one object to the other
Coulomb’s Law
3 parts:1. Any two charged objects will create a force
on each other2. Opposite charges will produce an attractive
force (such as N and S pole of magnet)3. Similar charges will produce a repulsive force
(such as N and N side of magnet)
Electric Field
Electric Field - region in space where electric forces act on charges
Lightning over Icelandic Volcano 2010
Lightning
Big static electric sparks occur when opposite charges between clouds or between the clouds and the ground try to neutralize
Can happen from sky to ground or ground to sky
Video
Lightning Safety Tips
Avoid water Avoid high ground Avoid open spaces Avoid metal objects Electricity will follow shortest path to the
ground, make sure that isn’t through YOU!
If in an open area, lay flat on the ground If you are in a car, stay in it, you are
SAFE, anyone know why?
Faraday Cages
Metallic enclosures that prevent the entry or escape of an electromagnetic field
A CAR is basically a faraday cage! Electricity will travel around metal shell of the
car and into the ground and will not go through it
Sweet Home Faraday Suit Video
ALTERNATING CURRENT & DIRECT CURRENT
Direct Current
Flow of charge always in one direction Battery charged objects
Alternating Current
Flow of charge back and forth, changing its direction many times in one second. Plugs and outlets / household
Is AC or DC better?
Advantages of Alternating Current: Voltage can be raised or lowered More efficient over long distances
How is Electricity Measured?
Volts-measure of the force or pressure under which electricity flows
Amps-measure of the flow rate of electrons or how much current moves through the wire in 1 second
Watt-measure of electrical power created Water Faucet analogy
Faucet turned on all the way-high voltage and amps
Faucet barely turned on dripping water-low voltage and amps
Ohm’s Law
Watts=Volts x Amps or W=V x A