Essential Questions:
What is electricity and how does it relate to energy?
What makes a circuit and what are the different types of circuits?
What is the relationship between voltage, resistance and current?
Electricity 101
• Electricity is the flow of electrical charge
(electrons)
• Electricity is a secondary source (made from
primary sources: coal, fuel, natural gas, oil…)
• Electricity is one of the most
widely used forms of energy.
Brainstorm….
Can you list 5 ways that you use
electricity on a daily basis?
Electricity 101
• We tend to take electricity for granted, but
electricity helps us in many ways
– Cooling/heating our homes
– Lighting our homes and school
– Powering television and appliances
– Charges our cell phones
Electricity 101
• The flow of electrons through a closed
circuit.
What do you suppose happens to the electron flow
when the circuit opens?
Two types of electricity
STATIC CURRENT
Static
Electricity
Static Electricity
• If you have ever been
shocked, you have
experienced static
electricity.
• Static electricity is the
accumulation of excess
electric charges on an
object.
Static Electricity
• There is a rule
associated with
static electricity
• Opposite Charges
Attract; Like Charges
Repel
What Causes Static Electricity?
• Most objects have a neutral charge
(equal numbers of protons and electrons)
• When one object rubs up against another
object, electrons are transferred
between the two objects and both
objects become charged!
Building Up Charge
• When an object becomes charged, the
charge is neither created or destroyed
(Law of Conservation of Charge)
• Charge can only be transferred!!!
Examples of Static Electricity
• Getting shocked when touching a metal door
knob
Examples of Static Electricity
• Hair standing up when rubbed with a balloon
Examples of Static Electricity
• Clothes sticking together in the dryer
Build up of charges
through
conduction- when
objects touch
Lightning When a charged
object gets near a
conductor
• Objects can transfer
electric charge (induction)
• When clouds form, they
rub up against each other
and become charged,
opposite charges attract
from the ground to the
sky.
Static Electricity Explained
Click for Video!
https://www.youtube.com/watch?v=yc2-363MIQs
Friction
Charges that results by objects
rubbing against each other.
Conduction
Charges that result by direct
contact.
Induction
Charges that result by objects
that do not come into contact.
Quick Activity
1. Blow up the balloon at your station. Rub this
balloon against your hair/shirt. Is this transfer of
e- an example of conduction, induction, or
friction? Explain.
1. Turn on the faucet at your station so that the
water flows in a steady stream. Take the
charged balloon and slowly approach the
stream of water. Is this phenomena an example
of conduction, induction, or friction? Explain.
1. Now take the charged balloon and move it
toward the tissue paper on your station. Is this
phenomena an example of conduction,
induction, or friction? Explain.
Current
Electricity
Current Electricity
– Current electricity is the flow of electrons through
a circuit.
– A circuit is a complete, closed pathway for
electricity.
– Conductors allow electricity
to flow easily. (Ex. Copper)
Types of Current Electricity
• Generators produce electric
current as a coil of wire moves
through a magnetic field.
• As the coil rotates, the direction
of the electric flow constantly
reverses direction.
• This is called an alternating
current (AC).
• AC is used to deliver power to
houses, office buildings, etc.
Examples of AC Current
Most home
appliances
run on AC
current.
Alternating Current
Types of Current Electricity
• Batteries can produce an electric current from
chemical reactions.
• Electrons are produced from the chemical reaction
inside the battery.
• Batteries produce direct current (DC) which flows in
only one direction.
Direct Current
How do we get our electricity?
• Research:
• Have you ever wondered why the lights
turn on with just the flick of a switch?
• In groups of 2 or 3, research where our
electricity comes from.
• Create an illustration/diagram that shows
the path of electricity from its original
source to a device that is powered by
electricity.
• Be prepared to share with your
classmates!
How do we get our electricity?
5
Measuring
Electricity
Measuring Electricity
• Electricity can be measured a number of ways.
– Current
– Resistance
– Voltage Click for Video!
https://www.youtube.com/watch?v=8gvJzrjwjds
Task:
Use the
illustration resistance
to create your
own
descriptions
for the terms:
current
Voltage voltage
Current
Resistance
Clipart Credits: http://www.sengpielaudio.com/calculator-ohmslaw.htm
Current
• Electric current is very similar to a flowing river.
• With electricity, current (I) is a measure of the
amount of electrons transferred over a period of
time.
• The electrons move through conductive materials
such as copper wire
• Amps is the unit for current
Voltage
• Voltage is the force that causes charges to
flow. (Think about it as pressure)
• Unit: volts
Resistance
• Resistance is the tendency for a material to
oppose the flow of electrons.
• Unit: ohms Ω
• Conductors have less resistance than insulators
– Ex. Copper
Resistance will
oppose
electron flow
through a
conductor
Ohm’s Law
• A formula used to measure resistance, current and/or
voltage.
• Resistance is directly proportional to voltage &
inversely proportional to current
– Resistance = voltage/current
– Current = voltage/resistance
– Voltage = current x resistance
Units
• Voltage = Volts
• Resistance= Ohms
• Current = amps
Flowing Electrons
• Ohm’s Law:
Example: What is the resistance of a circuit if the
current is 4 amps and the voltage is 12 volts?
Answer: R=V/I = 12 V / 4 amps = 3 Ohms
Ohm’s Law Practice
Complete the Ohm’s Law practice problems.
PARALELL VS. SERIES
Series Circuit
• Only one path is provided for electric current.
Series Circuit
• In a series circuit, the voltage is divided
amongst the load (assuming each bulb is the
same wattage)
60 V 60 V
120 V
What if a third bulb was added? A fourth?
Parallel Circuit
• Alternate paths or branches are provided for
electric current.
Parallel Circuit
• In a parallel circuit, each load (bulb) gets the
full voltage.
120 V 120 V 120 V 120 V
What if a fourth bulb was added?
Build a Circuit
Virtual Lab Website:
http://thefusebo
x.northernpower
grid.com/page/ci
rcuitbuilder.cfm
A circuit consists of a power source (like a battery), a conductive material (copper wire),
and some object that needs to be powered (like a light bulb).
In this virtual lab activity, you will use your knowledge of circuits to follow a step of
instructions to create circuits that will perform different tasks. As you complete each
task, you will be directed to a new level.
Goal: Complete all levels in the circuit lab
Series and Parallel Circuit
Practice
Complete the series and parallel circuits worksheet.
