unit 27 energy

8/6/2019 Unit 27 Energy

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Science Interactive LTD

Science Interactive LTD. PO BOX 50764 LONDON NW6 9AT email: [email protected] web: www:science-interactive.co.uk

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Science base multimedia CD-ROM for PC is a collection of 38 units or tools totalling over 1150PowerPoint slides . Each unit covers a wide range of different delivery and learning styles, offering anexciting way to involve your pupils during lessons or revision sessions. All styles of teaching and

learning are supported through use of high quality images , graphics , challenging exercises andquestions . Units can be used in the classroom via an interactive whiteboard , data projector or usedduring individual study via a PC or school network .

Unit 19: The Transitional Metals

Unit 18: Metals and their Properties

Unit 17: The Alkali MetalsUnit 16: The Periodic Table and its Elements

Unit 15: Genetic Engineering

Unit 14: Evolution and Human Impact

Unit 13: Inheritance and Selection

Unit 12: Mitosis and Meiosis

Unit 11: Flow of Energy and Elements through the Environment

Unit 10: Water Transport in Plants

Unit 9: Photosynthesis in Green Plants

Unit 8: Drugs and Bad Body Maintenance

Unit 7: Hormones and the Endocrine System

Unit 6: Human Homeostasis

Unit 5: Nervous System and the Senses

Unit 4: The Respiratory System

Unit 3: Healthy Body and Immunity

Unit 2: The Circulatory System

Unit 1: The Digestive System

Unit 38: Cells, Tissue, Organs and Organs systems

Unit 37: Natural Forces

Unit 36: Sound and HearingUnit 35: The Alkaline Earth Metals

Unit 34: The Earth and Plate Tectonics

Unit 33: Earth and Space

Unit 32: Newton's Forces and the Effects of Forces

Unit 31: Radioactivity

Unit 30: Light and the Electromagnetic Spectrum

Unit 29: Electricity

Unit 28: Generating Electricity and its Domestic Use

Unit 27: Energy

Unit 26: Rates of Reaction

Unit 25: The Noble Gases, their Properties and Uses

Unit 24: The Halogens, their Uses and Compounds

Unit 23: Ionic and Covalent Compounds

Unit 22: Elements, Molecules and Compounds

Unit 21: Rock Cycle

Unit 20: Crude Oil and its Products


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Unit 27Energy


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Unit 27: EnergyUnit 27: Energy Science Interactive LTD Copyright 2005

Understand: Keywords:1. The different types of energy and that energy is

measured in joules.2. That energy cannot be destroyed or created,

only transformed from one type to another.3. How to calculate the energy efficiency of a

device.4. That heat energy can be transferred by

convection, conduction and radiation.5. Some of the major sources of energy including

fossil fuels.6. How we use energy around the home for

lighting, heating, cooking and leisure activities.

7. That reducing energy use can save money andreduce the need to combust fossil fuels like oiland natural gas.

8. That using renewable methods of generatingelectricity provides alternatives to meeting theenergy demands of a population.

Energy, Chemical, Gravitational, Potential,Elastic, Kinetic, Sound, Light, Heat,Electrical, Transformed, Transferred, Device,Joule, Kilojoules, Sources, Fossil, Fuels,Efficiency, Renewable, Solar, Power, Tidal &

Geothermal .

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Types of energyTypes of energyEnergy cannot be destroyed or created, it can only be transformed from one type to another using a d_________. Energy is measured in joules, for example a 60 watt light bulb uses 60

joules of electrical energy per second. A kit Kat contains about 900 kilojoules of c___________ energy. There are eight forms of energy .Energy types: Word bank: device chemical

______________ ? ______________ ?

______________ ? ______________ ?

______________ ? ______________ ?

______________ ? ______________ ?

Examples

Diagram

ElasticChemicalSoundHeatType

London eye ______________ ?

Kinetic

Light bulb ______________ ?

______________ ? ______________ ?

______________ ? ______________ ?

Examples

Diagram

Type Electrical Gravitational Light



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Energy and the jouleEnergy and the joule oneoneEnergy is measured in units called joules . Using joules allows you to compare how muche_________ in joules, something uses per second ( e.g. a light bulb ) or contains ( e.g. chocolate

bar .) The joule is a very small unit of energy. For example; to lift a 100 g weight, one metreabove the Earths surface , one joule of energy is used. Compare this to the energy contained ina Kit Kat which is approximately 900 kilojoules or 900,000 joules. That means to burn off theenergy in one Kit Kat, you would have the lift the 100 g weight one metre above the Earths

surface a mere 900,000 times !Energy and the joule: Word bank: energy

A 900 watt hairdryer will use 900 joules of electrical energy per

second. How many joules would thishairdryer use in oneminute ?

Hairdryer

A burger meal with friesand a sugary fizzy drink supplies almost 5000 kJ.

This is just under half thekilojoules you require for a whole day. Why is junk

food linked to obesity ?

A Kit Kat bar weighing just 50 grams contains900 kJ. If your daily

allowance is 12,000 kJ,how many kit kats can youeat to fulfil you dailyrequirements ?

A 60 watt bulb uses 60 joules per second a100 watt, 100 joules

per second. How muchwould a 100 watt light bulb use in 1 second, 5

seconds and 1 hour ?

Notes

Diagram

Bulb Chocolate Burger meal



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Energy and the jouleEnergy and the joule twotwoThe power rating of an appliance tells us the number of joules that it uses every secondand the overall p________ of the appliance. If you were choosing between a 300 watt and500 watt drill, you might choose the 500 watt drill if you had to drill through concrete.This is because the strength of the drill will be higher, therefore the 500 watt drill would

be more able to drill very hard concrete. Below are some examples of the power ratingsand the energy (Js -1) that these devices use, every second. Try looking for the power rating

of your computer and play station at home ? (found underneath or rear of the product)

Energy and the joule: Word bank: power

A hearing aid, one of thesmallest electrical devicesrunning off small watch

batteries uses only 0.0001 joules per second.

Hearing aid

A hair dryer has a power rating of 900watts and uses 900

joules of electricalenergy per second.

Hair dryer

Notes

Diagram

A city that has a population of about tenmillion people usesabout 30,000 million

joules per second.

City

A new born babyweighing just 6 kg andtaking their fist stepsuses about 25 joules per second.

Baby



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Sc e ce te act ve D Copy g t 005

Energy and the jouleEnergy and the joule threethreeThe table below demonstrates the energy in joules involved in different events, fromthe k________ energy of a moving alpha particle to the energy received in solar energy by Earth from the Sun : Remember that 1 kilojoule is equal to 1000 joules .

Comparing energy:10 -11 kJ 10 -6 kJ 10 -1 kJ 1 kJ 10 3 kJ

10 7 kJ 10 13 kJ 10 17 kJ 10 20 kJ 10 25 kJ

Word bank: kinetic

Energy received fromthe Sun in one year

Energy release from anuclear bomb

Energy used by the shuttlegoing into orbit

Energy contained inone litre of petrol

Event

Diagram

Energy(kJ)

Energy used by thehuman body for 1 day

Energy from a burntmatch

Energy required to lift a100 g weight

Kinetic energy of analpha particle

Event

Diagram

Energy(kJ)



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py g

Energy use by the human bodyEnergy use by the human bodyAn adult human (male) body requires about 10,500 kJ every day. This value can varydepending on your s____, whether youre pregnant, your job and the sports you play.

Men require more energy than women because of their larger bodies. Teenagers usuallyrequire more energy during puberty, because they are growing and are usually moreactive. The highest demand for e________ is by women who are breastfeeding their newborns. Newborns only require about 25% of the energy of a fully grown adult. What

happens to your body weight if you consume too many kilojoules of food energy ?

Human energy use: Word bank: sex energy

A sleeping adult uses about 100 Joules per second which is the same as a 100 watt light bulb. Anewborn only uses about 25 Joules per second. When we run, walk or hurdle this increases our useof energy. Athletes normally consume much more energy in their diet when they are in training.

Notes

325 Joules per second

Hurdling


Walking

J/second

Diagram


Sleeping


Running



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Energy transformationsEnergy transformations oneone

___ joules of k_______ energy

1000 joules of electrical energy700 joules of heat and s________ energy.

45 joules of l_____ energy

100 joules of electrical energy

__ joules of heat energy

Energy can be transformed from one type to another by using a d________ like a bulb, motor or buzzer. During energy transformation, some useful energy can be lostto the environment. A simple device like a light bulb, for example transferse__________ energy to light and h______ energy. Only the light energy is usefulenergy, with the heat energy being lost to the environment. Work out the energytransfers when you a) light a firework, b) digest a Kit Kat & c) Burn wood ?

Energy transformations: Word bank: device electrical heat

A hairdryer transforms electrical energy into which forms of energy ?

Diagram A light bulb transforms electrical energy into which forms of energy ?

Diagram



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Energy transformationsEnergy transformations twotwo


1,000 joules of electrical energy



500 joules of electrical energy __ joules of heat energy

100 joules of sound energy

Most devices in the home use electrical energy. They are able to transform electricalenergy to other forms including, kinetic, heat, light and sound. Look at the following examples and complete the table ?

Energy transformations: Word bank: light heat

10 joules of light energy

300 joules of electrical energy

290 joules of h______ energy

A toaster converts electrical energy into which forms of energy ?

Diagram

A television transforms electrical energy into which forms of energy ?

Diagram

A light bulb transforms electrical energy into which forms of energy ?

Diagram


hth


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60W

150W

150 J

120 J heat

30 J lightelectrical

50 J heat

electrical300 J kinetic

50 J sound

50 J heat

electrical300 J kinetic

50 J sound

electrical

150 J heat

500 J100 J

15 J sound

35 J light

Energy transfer diagrams show the relationship between the input energy and the output energy of adevice like a games console, vacuum cleaner and light bulb. During all energy transformations, some

energy is lost to the surroundings, for example a vacuum cleaner converts 500 joules of electricalenergy to 300 joules of kinetic energy and 200 joules to heat and sound energy. Only the kineticenergy is useful, with the heat and sound energy being lost to the surroundings. In the following examples, the useful energy is underlined.

Energy transformations:

Energy transformationsEnergy transformations threethree

Every second, a light bulbconverts 150 joules of electrical

energy into 120 joules of heatand 30 joules of light energy.The heat energy is lost to thesurroundings.

Every second, a Dyson converts 500 joules of electrical energy into 300

joules of kinetic energy, 50 joulesinto sound and 150 joules into heat.The heat and sound energy is lost tothe surroundings.

Every second, a games consoleconverts 50 joules of electrical

energy into heat, 15 joules intosound and 25 joules into light.This heat energy is lost to thesurroundings.

Notes

Light bulb (150 W)Dyson (500 W)

Transfer DiagramJs -1

Diagram

Console (100 W)

f d ff



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7500 kJ of e_______ energy

25 kJ of sound & light energy

75 kJ of heat energy

2500 kJ of heat energy

100 J of electrical

10,000 kJ of kinetic

100 kJ of electrical

Energy transformations and efficiencyEnergy transformations and efficiencyWhen energy is transformed into another form, some useful energy is lost to theenvironment or surroundings. The efficiency of a d_______ can be worked out usingthe following formula.

Energy transformations:

Energy efficiency = Useful energy out/total input energy x 100 (units %)

Word bank: device

Work out using the formula, the energyefficiency of a plasmatelevision ?

Three

Useful energy (red)

Work out using the formula, the energy

efficiency of a wind turbine ?

Two

One

Example Energy in Device

Calculation:45 J/100 J x 100= 45%

Energy efficiency

C d iC d iScience Interactive LTD Copyright 2005


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ConductionConductionHeat energy can be t___________ by conduction. When materials are heated, theatoms v_________ more. This kinetic energy can be passed from atom to atom in

conducting materials. Conduction happens in all materials, but in good conductorslike m_________, free electrons can transfer the heat energy more quickly. All metalsare good conductors of heat. Insulators do not have free e__________ and conductheat poorly. Explain why metals always feel cold to the touch, whereas wood for

example feels warm ?

Conduction: Word bank: transferred vibrating metals electrons

Direction of heat transfer

Hot Cold

In this picture, heat is conducted andtransferred by conduction. Heat energy

spreads out from the hot or warm regions(coloured in red) to colder regions(coloured in blue)

Conduction of heat energy

Heat energy is transferred by vibratingatoms passing on their kinetic energy to

adjacent atoms. Metals are good conductors because of their free electrons and highdensity.

Notes

Diagram

Conduction


C iC i


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ConvectionConvectionHeat energy can be transferred through l_________ and gases by convection currents.Warm gases and liquids are less d________ because their vibrating atoms take up lessspace. This means that warm air or liquids rise to the surface. In a hot water tank, theelectric element heats the water which then rises to the top. As the warm water rises,the cooler water sinks making sure that all the water is heated. Convection currents donot transfer heat energy through solid materials...why ?

Convection:

Hot

Cold

Word bank: liquids dense

This thermographshows how hot

liquids (coloured inred) rise to thesurface in this pot.

Example one

The lava lamp firstmade in the 1960s

makes use of convection currentsto produce its effect.

Example two

As atoms are heated they vibrate moreand occupy more space. The less dense

gases or liquids rise to the top, cool thensink. Explain why in colds oceansnutrients are continuously recycled ?

Notes

Diagram

Convection


R di tiR di ti


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RadiationRadiationHeat energy from the s____ and other hot objects can be transferred by radiation. Thistype of radiation is called infra red radiation and is part of the electromagneticspectrum. Infra red radiation can transfer energy through a vacuum and unlike heattransfer by c___________ or convection does not require a material to travel through.Although you cannot see this type of wave using your eyesight, your skin can feelinfra red because it has temperature receptors close to its surface. Why has your bodyevolved skin that can detected temperature changes ?

Radiation:

10 -2m 10 -4m 10 -6m

Infra red

Travels at 300,000 kms -1

Transfers energy

Travels through a vacuum

e.m. spectrum

The human body is

also a source of infrared radiation. Look at the above image !

Example two

All hot objects

emit heat as infrared radiation. Doesice emit infra red ?

All hot objects emit infra red radiation.

The Sun is the biggest source of infra redradiation. Over 10 23 kilojoules of heatenergy falls ontheEarths surface per year.

Notes

Diagram

Radiation Example oneWord bank: sun conduction


S f gSo rces of energ


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Sources of energySources of energyThere are two types of energy: Renewable and non renewable forms. Non renewable

fossil fuels like coal, natural gas and o_____ are rich in the element c_______, can becombusted with oxygen, producing energy in the form of h____. They are fossil fuels

because they are formed from once living organisms. Remember that solar energy wasthe original e_______ source. Burning fossil fuels produces carbon dioxide which istermed a greenhouse gas ...Why ?

Main forms of fossil fuels: Word bank: oil carbon heat energy

30-40 years300 years60-70 yearsLifeexpectancy

Heating, Generating electricityHeating, generating electricityHeating, Transport, generating

electricity

Uses:

Found with crude oil deposits.Remains of dead plants.Remains of dead insects andother organic material.

Source

Natural gasCoalOilFuel

Diagram

Generating electrical energy from fossil fuelsScie

Generating electrical energy from fossil fuelsnce Interactive LTD Copyright 2005


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Generating electrical energy from fossil fuelsGenerating electrical energy from fossil fuelsCombusting fossil fuels like c_____, and natural gas produces h______ energy whichis used to produce super hot steam. The steam drives the turbines which are made

from huge magnets surrounded by a copper coil. The movement of the copper coilacross a magnetic field induces a c_________ flow in the copper wire. Electricalenergy cannot be stored and is delivered instantly by the National Grid using anetwork of overhead wires and underground cables clean and e fficiently to every

home in Britain.

Fossil fuels to electricity: Word bank: coal heat current

The amount of electricitythat you use during ayear is calculated using

meter readings. Theelectrical energy can betransformed into manyother forms of energy.

Customer

Electricity is thentransported along a hugenetwork of underground

or over ground copper cables to various usersincluding schools, homesand factories.

Transmission

Notes

Diagram

Non-renewable fossilfuels containing ancientenergy is extracted

from deep underground.These fuels includecrude oil, natural gasand coal.

Fuel

Combusting fossil fuelsgenerates large amountsof heat energy which in

turn boils water producing steam. Thisdrive turbines producingelectricity.

Power station

Renewable energy sourcesRenewable energy sourcesScience Interactive LTD Copyright 2005


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Renewable energy sourcesRenewable energy sourcesElectricity is very clean at the point of use, but combusting fossil fuels containingsulphur causes acid rain. Carbon dioxide, another pollutant from burning fossil fuels

traps heat in the atmosphere, therefore causing the g_____________ effect. Manysources of energy that we currently use every day are now renewable . This means thatunlike coal and natural gas they are not used up. Many scientists are working todevelop the technology to use these renewable sources of energy to generate

e___________. It is estimated that World consumption of energy is only a small fraction of the total energy received by Earth from the Sun every year.

Overview of renewable energy: Word bank: greenhouse electricity

Wind: Wind farms could supply up to 20% of the energy we use every year. Solar: Solar cells usingsolar energy could power traffic lights and street lamps. Geothermal: This type of energy is onlyfound in certain volcanic areas like Iceland. Biogas: Biogas converts animal waste like manure fromfarms into methane using microbes. Hydroelectric: Using moving water, hydroelectric dams are ableto generate clean electricity.

Notes

BiomassGeothermal

Diagram

Wind Solar Hydroelectric


Hydroelectric powerHydroelectric power


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Hydroelectric power Hydroelectric power Hydroelectric dams use water to store g____________ potential energy. When the water isreleased by giant flood gates, the kinetic energy of moving water drives turbine generator

blades. As in other power stations, a current is induced and electricity is fed into the National Grid . Although this is a renewable c______ source of energy, the initial impactof constructing a dam and flooding the valley and surrounding areas is huge. Naturalhabitats and local biodiversity are often sacrificed for renewable energy. Not all areas are

suitable for hydroelectricity...explain why ?

Hydroelectric power:

Water stored behind the dam is releasedconverting gravitational potential energy to

kinetic energy and finally electrical energy.What type of weather conditions are required to make building dams economic ?

Generating electricity using water

Great barriers like theone picture above are

also used to controlflooding and generateelectricity.

The Hoover Dam builton the Colorado River

generates over onemillion kilowatts a dayof clean energy.

Notes

Diagram

Hoover dam Barrage dam

Word bank: gravitational clean

Biogas and biomassBiogas and biomassScience Interactive LTD Copyright 2005


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Biogas or m________ ( CH 4) is produced by fermenting organic matter like plant andanimal waste. M________ feeding on animal waste material (manure) produces methane

as a by product. This can be stored and used just like natural gas. Ethanol can also be usedas an alternative fuel source in cars. Sugarcane is grown, the sugar is extracted and thenfermented using y_________. The ethanol is then distilled and used just like p_________ and diesel in cars. In Brazil, 25% of all cars run off ethanol. Why does Britain not grow

sugarcane to produce ethanol ?

Producing ethanol and biogas:

Biogas and biomassBiogas and biomass

Word bank: methane micobes yeast petrol

et hanol e t h

a n

o l et hanol

e t h

a n

o l

Animal waste, like horse manure is used by bacteria to produce biogas. This is identical

to natural gas. Unlike natural gas which is afossil fuel, it can be produced over and over again.

Sugarcane is grown using large amounts of land in hot climates. The sugar is converted to

ethanol using yeast. Ethanol performs just aswell as petrol and reduces exhaust pollutantslike sulphur and carbon monoxide.

Notes

Diagram

Animal waste BiogasSugarcane Ethanol


Tidal powerTidal power


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Tidal power Tidal power Tides and waves cause local water levels to r______ and fall. A barrage dam trapsw_______ at high tide. When the tide goes down again, the water can be released. The

flowing water turns the turbine generators to generate e_____________. As withhydroelectric dams, flooding can lead to the loss of habitats for many species that livealong river estuaries. Offshore underwater turbines ( wave generators ) can also use the riseand fall of water caused by waves or tides to generate electricity. Why is this a good choice

for renewable energy for countries like England ?

Energy from waves: Word bank: rise water electricity

Offshore wave generators like those pictured above,have little or no impact on the environment unlike

barrage dams. The turbine blade is turned bymoving water, which in turn generates an electriccurrent.

Kinetic energy of moving water isshown by this picture. Wave energy ishighest during the winter months.What causes waves in the seas and oceans ?

Notes

Diagram

Kinetic energy from waves Offshore wave electricity generators


Geothermal energyGeothermal energy


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Geothermal energyGeothermal energyWhere the Earths crust is thin or where it contains large amount of radioactive substanceslike Uranium 235 a ready heat source from hot rocks is available. Water can be

superheated producing s_______. Inside a geothermal power station, steam turns a turbinewhich generates electricity. If the water temperature is lower, it can be used to h______

peoples homes. Iceland has many hot springs and volcanic regions and make use of itsnatural geothermal energy. Iceland has so much geothermal energy that residents receive

free heating and electricity for their homes !

Geothermal energy:

A natural sources of steam which drives turbines

capable of producing electricity. Pipes that go deepunderground deliver either steam for generators or hot water for home heating.

The outflow of this geothermal power

station in Iceland has become a touristresort ideal for hot bathing It isknown as the blue lagoon.

Notes

Diagram

Geothermal energy in Iceland Geothermal energy generating electricity

Word bank: steam heat


Renewable wind powerRenewable wind power


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Renewable wind power Renewable wind power Pressure differences in the Earths atmosphere causes winds that blow across countries andcontinents. Wind is moving air that has k_________ energy. This energy can be used or

captured to drive a wind turbine generator . The blades are turned by the wind, which inturn makes a generator turn. This induces an electric current. Wind generators or farms arefound in w________ places like offshore or in mountainous areas. Although these windfarms dont create pollution, many people object to how they spoil the view. Are these

people justified in their views or should we continue to burn fossil fuels in order to generate our electricity ?

Wind energy: Word bank: kinetic windy

Wind farms are usually located offshore to avoid visual andnoise pollution. Also wind speeds are higher away fromland. Wind generators like the one pictured above will beused more and more in the future. Each one generatessufficient energy for around 1000 homes.

A single hurricane expends up to 10 15 kiloJoules during its short life. The governmentswant about 20% of the UK electricity to begenerated this way. It is clean, renewableand relatively cheap.

Notes

Diagram

Hurricane Wind farms and inside the wind turbine


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Cost of electrical energyCost of electrical energy


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Cost of electrical energyCost of electrical energyIn all homes supplied with electricity, a meter records how many u_______ of electricity you have used. The current cost of electricity is about 5 pence a kilowatt hour (kWh.) This cost is only an average cost, with electricity generated from somesources like solar and n________ power costing much more. Using electricity fromhydroelectric dams and burning fossil fuels like natural gas costs much less. You cannow choose to have only green electricity supplied to your house at a cost of 10

pence a kWh. What supplies green electricity and why does it cost most than other sources like fossil fuels ?

Overview of energy costs: Word bank: units nuclear

Each method of generating electrical energy has its advantages and drawbacks. Considering,cost, pollution, ease of use and cost of set up which is the best method of producing electricity ?

Notes:10 pence

Nuclear

2 pence

Hydroelectric

5 pence10 pence16 pence4 penceCost/kWh

Biogas

Diagram

Wind Solar Fossil fuels


Energy use in the homeEnergy use in the home


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Energy use in the homegyEnergy supplied to homes, schools, hospitals and industry needs to be immediate and reliable .The national grid supplies electrical energy at the flick of a s_________. Demand for electrical

energy varies during the day, with peak demand in the morning and during working hours. Thelowest demand is during the n________. Power companies use reliable sources of energy likenuclear power to maintain a steady supply. When the demand is high, they can use energy

produced by gas fired or hydroelectric power stations. These can be started relatively quickly

and cope with peak demands . When are these peak periods likely to occur ?

Electricity use in the home: Word bank: switch night

The percentage of energy used in homes, offices and other building varies over the year. In thewinter the majority of energy is used for home heating and lighting. In the summer there isless demand because of the warm temperatures and long light evenings.

Notes:

4%

Cooking

7%42%47%

Diagram

Heating Lighting Other


Saving energy about the homeSaving energy about the home oneone


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g gyg gySaving energy makes good sense: It costs you less money , uses up less fossil fuels andreduces p________ of the environment. Both at work and at home, we can all save energy.

Modern buildings are fitted with loft and wall insulation and double gazing. Theseinnovations help reduce heat e________ escaping through windows, doors, walls andceilings. Although fitting insulation and double glazing in older homes can be expensive,the money you save on heating bills will eventually repay the initial cost of installation.

Saving energy about the home one Word bank: pollution energy

Insulating the cavities between your walls isthe most effective typeof insulation, reducingenergy lost from2,600Js -1 to 1,000 Js -1.

Wall insulation

Placing insulation foamunderneath carpets, tilesor wooden floorsreduces energy loss by40% from 1200 Js -1 to700 Js -1.

Fitting double glazingreduces energy loss byhalf from 900 Js -1 to450Js -1. Explain howwindow double glazing works ?

About 1500 Joules of energy is lost everysecond through theroof. Using insulationcuts this down to about500 Js -1.

Notes

Diagram

Loft insulation Double glazing Floor insulation


Saving energy about the homeSaving energy about the home twotwo


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g gyg gySaving energy is not just about reducing the amount of heat energy that e________ through the walls, floors, w_________ and loft. We can also use energy efficient devicesand a bit of common sense. Normal light bulbs are energy inefficient because they also

produce h______ energy. Energy efficient light bulbs use a fraction of the energy, but areable to produce the same amount of light. Common sense also plays a large part. Turningoff lights, boiling less water and wearing warm cloths indoors also saves energy and

reduces the amount of f_________ fuels that we use.

Saving energy about the home two Word bank: escapes windows heat fossil

Boiling a full kettle tomake a single cup of coffee wastes energy.Many modern kettlescan now boil a singlecup.

Boiling less water

Indoors, instead of turning up the heatingyou can wear a jumper.Reduce energy wastage

by closing doors andwindows.

At night, in any city or town, count the number of office buildings thatleave their lights on. Do

you do the same in your own house ?

Energy efficient bulbsuse only 12 wattscompared to normallight bulbs which useupto150watts. Explainthe difference ?

Notes

Diagram

Light bulbs Turning off lights Wear clothing


Saving energy at homeSaving energy at home


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g gyg gy

2600 Js -1

900 Js -1

Heat loss though the floor

Heat loss through the roof

Heat lossthrough windows

Heat lossthrough wall

1 5 0 0

J s

- 1

1 2

0 0

J s

-1

Heating

Lighting

2.5

2.0

1.5

1.0

0.5

0.0Light bulb (100W)

Laptop (180W)

Toaster (900W)

Drill (1200W)

Hair dryer (1500W)

Kettle (2000W)

Heater (2500W) 2,500

2,000

1,500

1,000

500

0

W a t t

s K i l o w a t t s

2.5

2.0

1.5

1.0

0.5

0.0Light bulb (100 W)

Laptop (180 W)

Toaster (900 W)

Drill (1200 W)

Hair dryer (1500 W)

Kettle (2000 W)

Heater (2500 W) 2,500

2,000

1,500

1,000

500

0

W a t t s

K i l o w a t t s

Energy use by different devices

Picture to the left is how energy is used and lost inan average home. Using the information above,work out how you can save energy at home. Think how you can save energy used for lighting and

heating. Also how can you reduce heat loss in your home, through the walls, windows, roof space and floors ?

Earths fossil fuels are a finite resource and we can all do our bit to reduce the amount of energythat we consume at home or in the office. New houses are required to be energy e__________ withloft and wall insulation, efficient gas boilers and double glazing. How we live and respect the Earthsresources is important. Just switching off l_______ bulbs, reducing the central heating or not leavingour computer running saves energy and of course money. You can also opt to use renewable energy

purchased from your electricity supplier.

Saving energy at home: Word bank: efficient light


Cars of the futureCars of the future ??


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Using h__________ fuel cells in cars and buses as an alternative to using petrol and dieselis now a real possibility. In 2003 London Buses took delivery of four buses than run usingthe reaction between hydrogen and oxygen producing w________ as a waste product.These buses cost over one million pounds each but reduce pollution to zero at the point of use. The hydrogen is supplied by splitting water using green electricity . In the very near future, all cars and buses could be using hydrogen fuel cells.

The hydrogen powered car: Word bank: hydrogen water

The car of the future ? Imagine your exhaust emitting only water. Not just

a distant dream but soon a realitywhen the costs of design andmanufacture comes down.

Hydrogen car

A current drives anelectric motor producing

movement. The surplusenergy can be stored in a

battery.

Hydrogen and oxygenfuses together forming

water as a waste liquid and power in the form of electricity.

Notes

Diagram

Hydrogen fuel cell How it works


Extension questions and homework


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Direction of heat transfer

Hot Cold

1: Define the following terms: Energy, Device, Joule, Kilo-joules, Fossil-fuels, Efficiency & Renewable.

2: Look at the three pictures below. Complete the table.

3: Answer the following:

a) List three ways that heat energy can be lost from a house to the environment.

b) Explain how double glazing your house can reduce heat loss and your heating bill.

c) Explain how the air in expanded polystyrene coffee cups helps keep your coffee warm.

d) How does a foil blanket keep you warm and protect you from hypothermia.

e) How does a thermos flask keep your drink warm.f) Which saves more money: Double glazing or loft insulation.

g) Two houses: One with snow still on the roof, one without. Which is the most energy efficient house and why.

How is energy transferred ?

Radiation

Convection

Conduction

ExamplesTransfer method


4: Look at the information in the table below. Answer the questions:


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a) Work out the pay back period for each method of insulating your house.

b) Which is the most cost effective method of saving energy.

c) Why does it take so long to recoup the cost of double glazing your home.

d) Why does loft insulation save most energy and money.

d) Think of two other methods for insulating your house.

5: a) Name four fossil fuels and four renewable sources of energy.

b) Explain how burning fossil fuels increases the (i) the greenhouse effect & (ii) acid rain.

c) Place these fuels in order, starting with the one that produces most carbon dioxide: Coal, Oil, Gas, Petrol.

d) Why are solar cells not suitable for generating high current electricity for large towns and cities.

e) Why is green electricity more expensive than energy generated by burning fossils fuels.e) Give two ways in which the following may damage and benefit the environment.

(i) Hydroelectric dams (ii) Solar cells (iii) Hydrogen fuel cell cars (iv) Biogas (v) Wind farms (vi) Geothermalenergy.

HighHigh (195)Moderately expensive (2450)Wall insulationHighHigh (250)Inexpensive (450)Loft insulation

Low (150)

Saving each year

LowExpensive (8000)Double glazing

Cost effectivenessInitial costInsulating method

Internet:Go to google.co.uk and find about how the combustion of fossils fuels produces acid rain and the greenhouse effect.Also find out about cars and buses powered by hydrogen fuel cells.

unit 27 energy

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