Force, Energy & Communication Lesson 3 - 4
Force, Energy & Communication Lesson 3 - 4. Lesson Objectives To be able to explain what happens with a Van De Graaff generator. To describe some practical.
Dec 30, 2015
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Force, Energy & Communication
Lesson 3 - 4
Lesson Objectives
To be able to explain what happens with a Van De Graaff generator.
To describe some practical applications of static electricity
To be secure in the vocabulary of electricity To know an be able to use Q = It and P =IV To appreciate differences in the amount of
electricity used by different appliances.
Van de Graaf
Van de Graaff – how it works
Stick the picture of the Van de Graaff in your exercise books.
Read the sentences that follow. Decide on the most logical order to put the
sentences in. Copy the sentences into your book in the
correct order
Van de Graaff – how it works
This happens because the charge is deposited on the bottom of the belt.
If too much charge builds up on the dome it discharges itself by letting sparks fly to any nearby object.
The Van de Graaff generator is a machine for charging things up.
When switched on, charge builds up on its dome. The charge is carried up to the dome by the belt. Any insulated object connected to the dome is
charged too.
Van de Graaff – how it works
1. The Van de Graaff generator is a machine for charging things up.
2. When switched on, charge builds up on its dome.3. This happens because the charge is deposited on
the bottom of the belt.4. The charge is carried up to the dome by the belt.5. Any insulated object connected to the dome is
charged too.6. If too much charge builds up on the dome it
discharges itself by letting sparks fly to any nearby object.
Uses of static electricity
You will be given this information sheet.
It has 4 sections. You are to make notes
on each four sections by using bullet points.
No more than 4 bullet points per section.
e.g. …..
Uses of static electricity
Electrostatic precipitator Used to remove particles
from power station smoke Particles in smoke are given
a positive charge They are attracted to large
plates with negative charge. Particles then easily
removed from plates. Easy!
Uses of static electricity
You will be given this information sheet.
It has 4 sections. You are to make notes
on each four sections by using bullet points.
No more than 4 bullet points per section.
e.g. …..
Key word glossary
CHARGE ….
Key word glossary
CHARGE ….a store of electricity, usually caused by electrons
Key word glossary
CHARGE ….a store of electricity, usually caused by electrons
CURRENT …
Key word glossary
CHARGE ….a store of electricity, usually caused by electrons
CURRENT … a movement of electrical charge.
Key word glossary
CHARGE ….a store of electricity, usually caused by electrons
CURRENT … a movement of electrical charge
AMPS…
Key word glossary
CHARGE ….a store of electricity, usually caused by electrons
CURRENT … a movement of electrical charge
AMPS… a measure of the amount of charge in a current
Key word glossary
CHARGE ….a store of electricity, usually caused by electrons
CURRENT … a movement of electrical charge
AMPS… a measure of the amount of charge in a current
VOLTAGE….
Key word glossary
CHARGE ….a store of electricity, usually caused by electrons
CURRENT … a movement of electrical charge
AMPS… a measure of the amount of charge in a current
VOLTAGE….the amount of force on a charge
Goodie! Time for some equations.
Goodie! Time for some equations.
You need to KNOW these equations.
Charge and current
Electric charge is measured in coulombs, C.
One coulomb is defined as the amount of charge passing a point in the circuit each second, when the current is one amp.
Charge and current
In other words, a current of one ampere is equal to a rate of flow of charge of one coulomb per second.
For a steady current in a circuit
Charge passed = Current X Time
(coulombs) (amperes) (seconds)
Q = I t
Electric power
Important revision!! Power is a measure of
how much energy there is per second.
Energy is measured in joules
Time is measured in seconds
So power is measured in joules per second
Electric power
BUT “joules per second” is a bit of a mouthful.
So we use another unit.
1 joule per second is called 1 watt
Electric power
The power within a circuit can be worked out if the current and voltage are known, using the following equation.
Electric power
The power within a circuit can be worked out if the current and voltage are known, using the following equation.
Electrical power = Current X Voltage
(watts) (amps) (volts)
P = I V
Electric power
The power within a circuit can be worked out if the current and voltage are known, using the following equation.
Electrical power = Current X Voltage
(watts) (amps) (volts)
P = I V
The more power something the uses, the more electricity it uses, the more expensive it is to run!
We will be back to those equations later
…. You will need them for your homework!
Power – who is paying the bill You will be given an envelope with pictures of
a number of appliances in them.
Take out the pictures and arrange them in a league table, with the appliance which you think uses the most electricity at the top and the one that uses the least at the bottom.
Power – who is paying the bill Complete this table
Power – who is paying the bill Copy and complete this table
Appliance Current, I Voltage, V Power
(amps) (volts) P = I x V (watts)
Television 0.83 240
Iron 4.0 240
Car headlamp 12 48
Hi-fi 0.83 200
Hairdryer 2 240
Lightbulb 0.25 60
Kettle 10 240
Power – who is paying the bill Copy and complete this table
Appliance Current, I Voltage, V Power
(amps) (volts) P = I x V (watts)
Television 0.83 240 200
Iron 4.0 240
Car headlamp 12 48
Hi-fi 0.83 200
Hairdryer 2 240
Lightbulb 0.25 60
Kettle 10 240
Power – who is paying the bill Copy and complete this table
Appliance Current, I Voltage, V Power
(amps) (volts) P = I x V (watts)
Television 0.83 240 200
Iron 4.0 240 960
Car headlamp 12 48
Hi-fi 0.83 200
Hairdryer 2 240
Lightbulb 0.25 60
Kettle 10 240
Power – who is paying the bill Copy and complete this table
Appliance Current, I Voltage, V Power
(amps) (volts) P = I x V (watts)
Television 0.83 240 200
Iron 4.0 240 960
Car headlamp 4 12 48
Hi-fi 0.83 200
Hairdryer 2 240
Lightbulb 0.25 60
Kettle 10 240
Power – who is paying the bill Copy and complete this table
Appliance Current, I Voltage, V Power
(amps) (volts) P = I x V (watts)
Television 0.83 240 200
Iron 4.0 240 960
Car headlamp 4 12 48
Hi-fi 0.83 240 200
Hairdryer 2 240
Lightbulb 0.25 60
Kettle 10 240
Power – who is paying the bill Copy and complete this table
Appliance Current, I Voltage, V Power
(amps) (volts) P = I x V (watts)
Television 0.83 240 200
Iron 4.0 240 960
Car headlamp 4 12 48
Hi-fi 0.83 240 200
Hairdryer 2 240 480
Lightbulb 0.25 60
Kettle 10 240
Power – who is paying the bill Copy and complete this table
Appliance Current, I Voltage, V Power
(amps) (volts) P = I x V (watts)
Television 0.83 240 200
Iron 4.0 240 960
Car headlamp 4 12 48
Hi-fi 0.83 240 200
Hairdryer 2 240 480
Lightbulb 0.25 240 60
Kettle 10 240
Power – who is paying the bill Copy and complete this table
Appliance Current, I Voltage, V Power
(amps) (volts) P = I x V (watts)
Television 0.83 240 200
Iron 4.0 240 960
Car headlamp 4 12 48
Hi-fi 0.83 240 200
Hairdryer 2 240 480
Lightbulb 0.25 240 60
Kettle 10 240 2400
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