Question: What happens when I switch on the TV?
End Product: Discussion of the environmental impact of electricity generation.
Objectives - To understand how our electricity is generated and how it affects the environment
Timing - Up to 7 lessons
Electricity is a very important type of energy to us as it can easily be transferred to other types. Traditionally it was generated using fossil fuels but we are now having to rethink this and are starting to use alternative methods such as wind and solar power which you will look at in the "Solar Panels" section.
Draw a table with the following headings:
Use www.bbc.co.uk/bitesize, www.s-cool.co.uk, www.gcse.com, http://www.eia.doe.gov/kids/energyfacts/index.html
or http://tacoma.apogee.net/kids/explore.aspx
to fill in your table in as much detail as possible. Consider cost, availability and environmental impact.
You are now going to look at how burning fossil fuels is used to generate electricity for our homes. Use S-Cool and http://www.bbc.co.uk/schools/gcsebitesize/physics/electricity_and_magnetism/electromagnetic_inductionrev2.shtml to read about how electricity is generated. Write down the different stages of generation from burning fossil fuels through to electricity reaching our homes. You may also use http://science.howstuffworks.com/power.htm - although there are some subtle differences between the British and American systems so be careful!
Your teacher may demonstrate how passing a wire through a magnetic field inducing an electric current in it. What affects how big the current is?
Also write down the useful and wasteful energy transfers for a power station. (You should also have looked at efficiency in the "Heating Bill" section of the project). Write down an efficiency equation for a power station.
Make sure you understand in detail how a generator works - does it produce alternating current ac or direct current dc? (You should have looked at this in the "Solar Panels" section as well). What is the frequency of the British mains supply and what does this mean? What's the difference between a generator and a dynamo and how can you increase the current generated?
What is the National Grid?
Now describe in detail how a transformer works (you don't need to know the equation for transformers). Why is a high voltage and low current used to transmit electricity across the National Grid?
Your teacher may demonstrate a demountable transformer and you can also try different combinations of coils to see how transformers work.
Try the following worksheets:
Q4-6 on the "Electricity and Magnetism" sheet
"Electricity - from the Power Station to your Home"