1. The National Grid
Starter
Write a definition of what you think ‘The national grid’ is and what it does
Understand the role of the National Grid in transporting electricity
ALL – state the different parts of the national grid
MOST – Describe the role of transformers in the national grid
SOME – explain the advantages and disadvantages of under/overground cables
KEYWORDS: Pylon, transformer, cables,
Current, voltage, power

2. LO: understand the role of the National Grid in transporting electricity
The national grid is a system of pylons, cables, power stations and transformers that are used to transport electricity all over the country

3. LO: understand the role of the National Grid in transporting electricity
Draw and label the national grid. Make sure you label the different parts and what the voltage is at different parts of the grid

4. LO: understand the role of the National Grid in transporting electricity
Transformers
Transformers are devices that either raise or lower the voltage. Step-up transformers raise the voltage and step-down transformers lower the voltage.

6. Task Advantages Disadvantages Overhead cables Underground cables
LO: understand the role of the National Grid in transporting electricity
Task
Advantages
Disadvantages
Overhead cables
Underground cables

7. The Cost of Electricity
Understand how to calculate the cost of electricity
ALL – state the definition of a kilowatt-hour
MOST – Perform simple calculations to find the cost of electricity
SOME – Perform calculations that require the rearrangement of a formula
KEYWORDS: Power, time, kilowatt-hour,
Electricity, cost of electricity

8. The Cost of Electricity
LO: understand how to calculate the cost of electricity
The Cost of Electricity
Electricity can be very expensive if you are not careful with how you use it. Make a list of all the things you do around the house to save electricity

9. Calculating the cost of electricity
LO: understand how to calculate the cost of electricity
Calculating the cost of electricity
To calculate how much it costs to run an appliance, you need to know three things:
Power
Time it is used for
The cost of electricity
Calculating the cost is a two step process!!!

10. Calculating the cost of electricity
LO: understand how to calculate the cost of electricity
Calculating the cost of electricity
E = p x t
Cost = number of units x cost per unit
E = energy (kilowatt hours - kWh)
p = power (kilowatt - kW)
t = time (hours - h)

11. LO: understand how to calculate the cost of electricity
Example 1
A kettle has a power rating of 0.5kW. On average, it is used for a total time of two hours every month. If electricity costs 8p per unit, how much does it cost to use the kettle every month?

12. LO: understand how to calculate the cost of electricity
Example 2
A builder is using a 3kW electric saw to cut pieces of wood. How much does it cost him to use the saw for 3 hours a day, if electricity costs 10p per unit?

13. Electricity costs 7p per unit for all these questions
LO: understand how to calculate the cost of electricity
Example questions
A kettle has a power rating of 2kW. On average, it is used for a total time of 1hour every week. If electricity costs 8p per unit, how much does it cost to use the kettle for a year? (Assume there are 52 weeks in a year)
How much does it cost to use a 2kW TV for 5 hours?
How much does it cost to use a 2.5kW Xbox for 6 hours?
How much would you save if you used a 1kW PS3 for the same amount of time as the Xbox in the question above?
A builder uses a 600W drill for 2 hours every day. How much does it cost him to use it for a year? (assume there are 365 days in a year)
Electricity costs 7p per unit for all these questions

14. LO: understand how to calculate the cost of electricity
True or False?
Copy down the true sentences and change the false sentences to make them true
The national grid is used to transmit telephone signals across the country
A transformer is a devices that is used to change the current and voltage in the national grid
A disadvantage of nuclear power is that it produces dangerous radioactive waste
A 1kilowatt device that is used for 2 hours uses 3 kilowatt hours of energy
An advantage of using fossil fuels is that they are unlimited and will never run out