Download Energy, Electricity, and Magnetism

Energy, Electricity, and
Magnetism
What is energy?
What is energy?
A. The ability to move an object over a
distance.
B. The ability to do work
Law of Conservation of Energy?
Types of Energy
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Chemical
Stored Mechanical
Mechanical
Gravitational
Potential
Kinetic
Nuclear
Radiant
Thermal
Electrical
Sound
How can we manufacture energy?
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Fossil Fuels-1
Biomass-2
Solar- 3
Hydroelectric- 4
Wind-5
Geothermal- 6
Nuclear- 7
Renewable resources are materials that can be replaced
through natural and/or human processes.
• Nonrenewable resources exist in fixed amounts within the
earth and once they’re used up, they’re gone forever or it
takes the earth an extreme amount of time to make them.
Fossil Fuels
• Coal, Petrol, Natural Gas
• Formed during the CARBONIFEROUS period,
organisms (like algae/zooplankton) exposed to
heat and pressure- but not air
• Coal- Mine
• Natural Gas- Frack (drill, pump in water
solution, capture escaping gas from shale,
repeat)
• Petroleum/ Crude Oil- Drill and refine into
different combinations of hydrocarbons
Biomass
• Energy derived by processing once living things,
most often collected, burned to heat directly or
to heat water and turn a turbine for electricity
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Biodiesel/ ethanol- Corn and algae
Petrol- algae
Methane- manure
Direct Fuel- wood/ plant matter (burning)
Solar
Photovoltaic and Thermal
• Photo- photons- light to
make energy (DC current)
• Thermal- heat,
Water is heated and
Energy is transferred to
heat other water sources
Hydroelectric, Wind, Geothermal
• Why did I place these all together… TURBINES!
Water, air or steam move the blades of the
turbine and generate the charge needed for
electricity
• A turbine takes motion (mechanical energy)
and generates it into electricity.
It a GENERATOR (which we will discuss again later)
Nuclear
• This involves steam rotating turbines but HOW?
• Core or radioactive substance (usually Uranium),
immersed into pools of water
• Undergoes the process of fission, atom decays
into “smaller elements”
• During this process, energy in the form of heat is
released and creates steam which turns a steam
turbine
• These are in pressurized systems and can be
activated or cooled off. If it can not be cooled off
properly = “meltdown”
What is Electricity?
• Electricity is the movement of electrons,
flows from a negative charge to a positive
• Static stays in one place, is created when an object gives up
or gains electrons, moves from one surface to another
• Rubbing an inflated balloon on clothing or rubbing your
shoes on carpeting forms static electricity. Lightning is also
static!
• Electrical is a flow of electric charge, often carried by
moving electrons in a wire.
• (It can also be carried by ions in an electrolyte, or by both ions/electrons
in a plasma)
Tools to measure
• Multimeter
• Voltmeter
Galvanometer, an instrument used to indicate the
presence, direction, or strength of a small electric
current through movements of a magnetic needle in a
magnetic field
Transferring Charges:
Friction: the transfer of electrons from one
uncharged object to another by rubbing
Conduction: the transfer of electrons from
a charged object to another by direct
contact
Induction: creating voltage in a conductor
when exposed to a magnetic force
Units for energy and electricity
• joule (J) -The SI unit of energy (work) .
1kg ·m2 /s-2
What else is a joule?
Units for Electricity
Joules are also…
*Work necessary to move an electric charge of one coulomb through a
volt
Coulomb- SI unit of Electric charge, one amp in one sec (C or a * s)
Volt- electric potential energy between 2 points, “difference” (V)
*Work required to produce one watt of power for one sec
Watt- SI unit for power, J/s, power is the rate of doing work (W)
• KwH- kilowatt hours
• 1 kilowatt hour = 3.6×106 J (or 3.6 MJ)
Ampere
Amp- The amount of electric charge passing specific
point in an electric circuit per second
The measure of rate of flow of electrons.
I can change this by-increasing the number of charged particles
-the charge on the particles
-the speed at which the particles are moving past a
specified point
1A= C/S
Ohm’s
• The ohm (Ω) is the SI unit of resistance
• Ohm’s Law- a current through a conductive material
between two points is directly proportional to the
potential difference (volt).
Current (I) = Voltage
Resistance
Current- represented by I
or A (in amps)
WRITE THIS DOWN!! 
Practice Problems
• In a circuit there is a 0.5 A current in the bulb.
The voltage across the bulb is 4.0 V. What is
the bulb’s resistance?
• A waffle iron has a 12 A current. If the
resistance of the coils is 10 Ω, what is the
voltage?
Conductors and Insulators
• Material from which the wire is made.
Insulators = high resistance
• Glass, Plastic, Wood, Rubber
Conductors = low resistance
Metals (copper, silver), ionized solutions
Length, diameter, and temperature can affect
resistance
Magnets and Electromagnets
Magnet- material which has a field which attracts
other magnetic objects- ferrous materials
A magnet produced by an electric field is called an
electromagnet.
A coil of wire with a current is called a solenoid.
OPPOSITES ATTRACT!
3 characteristics of a magnetic field
produced by a current:
1. The magnetic field can be turned on or off
How? Turn the current off
2. The magnetic field can have its direction
changed
How? Reverse the direction of the current
3. The field can have its strength change
How? By winding a wire with a current into
loops, you strengthen the magnetic field in
the center of the coil.
• An electric current is induced (or caused) in a
conductor when it moves through a magnetic
field. This is called electromagnetic induction.
• In an induced current, charges may flow in
one direction or may alternate (go back and
forth). DC (direct current) go in one
direction. AC (alternating current) go back
and forth.
• AC current (alternating current) is used in
homes, schools and other buildings because
it can be “stepped down” for safer use.
Anything with an “outlet/plug”
• DC current (direct current) is used in batteries
and anything battery-powered, solar panels
• Edison vs. Tesla
Motors vs. Generators
• When electromagnets move a rod or axle
(which move something like the blades of a
blender) this is called an electric motor.
• A device that transforms mechanical energy
into electrical energy is called a generator.
• A generator use motion in a magnetic field to
produce an electric current.
• Notice:
An electric motor is a device for transforming
electrical energy into mechanical energy; an
electric generator does the reverse. It converts
mechanical energy into electricity.
INVERSELY RELATED!
A transformer is a device that increases or
decreases voltage. A transformer takes in
electricity at a higher voltage and runs it
through a wire with fewer coils. Having fewer
coils means less voltage. So the voltage is
"stepped-down.“
Electric Circuit
• Is the complete unbroken path through which
an electric charge can flow
• Series and Parallel
• Circuits need an energy source- batteries or
generators
Series
• Series Circuit: in a series circuit there is only
one path for the current to take
Parallel
• Parallel Circuit: in a parallel circuit, the
different parts of the circuit are on separate
branches
Batteries
• Wet Cell
• Dry Cell