AQAScience A Unit 3 P1.4 notes

7/30/2019 AQAScience A Unit 3 P1.4 notes

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GCN

Su

AQA

E Science Aew Unit 3

Physics

mmary Notes

Part 2

(P1.4)Prepared and compiled by

Steve Bishop


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Table of Contents

P1.4 Methods we use to generate electricity...................................................................... 2P1.4.1 Generating electricity ................................................................................................................ 3P1.4.2 The National Grid ...................................................................................................................... 11

P1.4 Methods we use to generate electricityVarious energy sources can be used to generate the electricity we need. We must carefully considerthe advantages and disadvantages of using each energy source before deciding which energysource(s) it would be best to use in any particular situation. Electricity is distributed via the NationalGrid.

I can:

evaluate different methods of generating electricity evaluate ways of matching supply with demand, either by increasing supply or decreasing demand compare the advantages and disadvantages of overhead power lines and underground cables.

Key wordsSupplyDemandGeneratorTurbineFossil fuelBiofuelRenewableNon-renewableNational gridTidalGeothermalPylonTransformer


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P1.4.1 Generating electricitya) In some power stations an energy source is used toheat water. The steam produced drives a turbine that iscoupled to an electrical generator.

Energy sources include:

the fossil fuels (coal, oil and gas) which are burned toheat water or airuranium and plutonium, when energy from nuclearfission is used to heat waterbiofuels that can be burned to heat water.

b) Water and wind can be used to drive turbines directly.

c) Electricity can be produced directly from the Sunsradiation.

d) In some volcanic areas hot water and steam rise tothe surface. The steam can be tapped and used to driveturbines. This is known as geothermal energy.

e) Small-scale production of electricity may be useful in some areas andfor some uses, eg hydroelectricity in remote areas and solar cells forroadside signs.

f) Using different energy resources has different effects on theenvironment. These effects include:

the release of substances into the atmospherethe production of waste materialsnoise and visual pollutionthe destruction of wildlife habitats.


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Wind power and wind turbines

Description

For Against

Solar energy

Description

For Against


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Hydroelectricity and pumped storage

Description

For Against

Wave power and tidal barrage

Description

For Against


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Geothermal

Description

For Against

Biomass

Description

For Against


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Coal

Description

For Against

Oil

Description

For Against


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Gas

Description

For Against

Nuclear

Description

For Against


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P1.4.2 The National Grida) Electricity is distributed from pow

There are four main stages:1. the fuel is burned to boil w2. the steam makes a turbine3. the spinning turbine turns4. the electricity goes to the t

er stations to consumers along the National Grid.

ter to make steamspingenerator which produces electricity

ansformers to produce the correct voltage


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b) For a given power, increasing the voltage reduces the current required and this reduces the energylosses in the cables.

c) The uses of step-up and step-down transformers in the National Grid.A transformer is an electrical device that changes the voltage of an alternating current (ac)supply, such as the mains electrical supply. A transformer changes a high-voltage supply into a

low-voltage one, or vice versa.A transformer that increases the voltage is called a step-up transformer.A transformer that decreases the voltage is called a step-down transformer.


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Underground or overground?

Use the following terms in the correct categories to compare underground and overground means oftransporting electricityA lot neededEasy

LowHard

HiddenHigh

Less reliableMore reliable

NoNot much needed

YesUgly

Overhead Underground

Set-up costs

Amount of looking after

needed?

Easy to get to if there is a

problem?

How does it look?

Affected by weather?

Reliability?

How easy to set up?


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Name three non-renewable energy resources

Name three renewable resources

Give three advantages of renewable energy resources

Name the energy obtained from underground.

Name the energy made from plants and waste

Complete the sentences:

Use these words (they may be used more than once)

decrease electricity generator heat increase turbine water

In a power station energy sources are used to produce h______ . The heat is used to boil

w_____ . The steam drives a t_________ . The t___________ is coupled to a

g___________. The g__________ produces the e__________ .

This is distributed to homes by the N__________ G________.

A step-up transformer is used to ____________ the voltage

A step-down transformer is used to ____________ the voltage.


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Label the diagram:

1.

2.

3.

4.

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AQAScience A Unit 3 P1.4 notes