Science Interactive LTD Copyright 2005
Science Interactive LTD
Science base multimedia CD-ROM for PC is a collection of 38 units or tools totalling over 1150
PowerPoint slides. Each unit covers a wide range of different delivery and learning styles, offering an
exciting 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 and
questions. Units can be used in the classroom via an interactive whiteboard, data projector or used
during individual study via a PC or school network.
Science Interactive LTD. PO BOX 50764 LONDON NW6 9AT email: sales@science-interactive.co.uk web: www:science-interactive.co.uk
Unit 1: The Digestive System Unit 20: Crude Oil and its Products
Unit 2: The Circulatory System Unit 21: Rock Cycle
Unit 3: Healthy Body and Immunity Unit 22: Elements, Molecules and Compounds
Unit 4: The Respiratory System Unit 23: Ionic and Covalent Compounds
Unit 5: Nervous System and the Senses Unit 24: The Halogens, their Uses and Compounds
Unit 6: Human Homeostasis Unit 25: The Noble Gases, their Properties and Uses
Unit 7: Hormones and the Endocrine System Unit 26: Rates of Reaction
Unit 8: Drugs and Bad Body Maintenance Unit 27: Energy
Unit 9: Photosynthesis in Green Plants Unit 28: Generating Electricity and its Domestic Use
Unit 10: Water Transport in Plants Unit 29: Electricity
Unit 11: Flow of Energy and Elements through the Environment Unit 30: Light and the Electromagnetic Spectrum
Unit 12: Mitosis and Meiosis Unit 31: Radioactivity
Unit 13: Inheritance and Selection Unit 32: Newton's Forces and the Effects of Forces
Unit 14: Evolution and Human Impact Unit 33: Earth and Space
Unit 15: Genetic Engineering Unit 34: The Earth and Plate Tectonics
Unit 16: The Periodic Table and its Elements Unit 35: The Alkaline Earth Metals
Unit 17: The Alkali Metals Unit 36: Sound and Hearing
Unit 18: Metals and their Properties Unit 37: Natural Forces
Unit 19: The Transitional Metals Unit 38: Cells, Tissue, Organs and Organs systems

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Unit 27
Energy

Unit 27: Energy Science Interactive LTD Copyright 2005
Understand: Keywords:
The different types of energy and that energy is Energy, Chemical, Gravitational, Potential,
1.
measured in joules. Elastic, Kinetic, Sound, Light, Heat,
That energy cannot be destroyed or created,
2. Electrical, Transformed, Transferred, Device,
only transformed from one type to another.
Joule, Kilojoules, Sources, Fossil, Fuels,
How to calculate the energy efficiency of a
3.
Efficiency, Renewable, Solar, Power, Tidal &
device.
Geothermal.
That heat energy can be transferred by
4.
convection, conduction and radiation.
Some of the major sources of energy including
5.
fossil fuels.
How we use energy around the home for
6.
lighting, heating, cooking and leisure activities.
That reducing energy use can save money and
7.
reduce the need to combust fossil fuels like oil
and natural gas.
That using renewable methods of generating
8.
electricity provides alternatives to meeting the
energy demands of a population.
Click mouse to begin
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Science Interactive LTD Copyright 2005
Types of energy
Energy 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
Type Electrical Gravitational Kinetic Light
Diagram
Examples ______________ ? ______________ ? London eye Light bulb
______________ ? ______________ ? ______________ ? ______________ ?
Type Heat Sound Chemical Elastic
Diagram
Examples ______________ ? ______________ ? ______________ ? ______________ ?
______________ ? ______________ ? ______________ ? ______________ ?

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Energy and the joule one
Energy is measured in units called joules. Using joules allows you to compare how much
e_________ 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 metre
above the Earth’s surface, one joule of energy is used. Compare this to the energy contained in
a Kit Kat which is approximately 900 kilojoules or 900,000 joules. That means to burn off the
energy in one Kit Kat, you would have the lift the 100 g weight one metre above the Earth’s
surface a mere 900,000 times !
Energy and the joule: Word bank: energy
Bulb Chocolate Hairdryer Burger meal
Diagram
A 60 watt bulb uses 60 A Kit Kat bar weighing A 900 watt hairdryer A burger meal with fries
Notes
joules per second a just 50 grams contains will use 900 joules of and a sugary fizzy drink
100 watt, 100 joules 900 kJ. If your daily electrical energy per supplies almost 5000 kJ.
per second. How much allowance is 12,000 kJ, second. How many This is just under half the
would a 100 watt light how many kit kats can you joules would this kilojoules you require for
bulb use in 1 second, 5 eat to fulfil you daily hairdryer use in one a whole day. Why is junk
seconds and 1 hour ? requirements ? food linked to obesity ?
minute ?

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Energy and the joule two
The power rating of an appliance tells us the number of joules that it uses every second
and the overall p________ of the appliance. If you were choosing between a 300 watt and
500 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 ratings
and 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
City Baby Hair dryer Hearing aid
Diagram
A city that has a A new born baby A hair dryer has a A hearing aid, one of the
Notes
population of about ten weighing just 6 kg and power rating of 900 smallest electrical devices
million people uses taking their fist steps watts and uses 900 running off small watch
about 30,000 million uses about 25 joules per joules of electrical batteries uses only 0.0001
joules per second. second. energy per second. joules per second.

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Energy and the joule three
The table below demonstrates the energy in joules involved in different events, from
the 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: Word bank: kinetic
-11 -6 -1 3
10 kJ 10 kJ 10 kJ 1 kJ 10 kJ
Energy
(kJ)
Diagram
Event Kinetic energy of an Energy required to lift a Energy from a burnt Energy used by the
alpha particle 100 g weight match human body for 1 day
107 kJ 1013 kJ 1017 kJ 1020 kJ 1025 kJ
Energy
(kJ)
Diagram
Event Energy contained in Energy used by the shuttle Energy release from a Energy received from
one litre of petrol going into orbit nuclear bomb the Sun in one year

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Energy use by the human body
An adult human (male) body requires about 10,500 kJ every day. This value can vary
depending on your s____, whether you’re pregnant, your job and the sports you play.
Men require more energy than women because of their larger bodies. Teenagers usually
require more energy during puberty, because they are growing and are usually more
active. 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
Sleeping Running Walking Hurdling
Diagram
J/second 100 Joules per second 300 Joules per second 175 Joules per second 325 Joules per second
Notes A sleeping adult uses about 100 Joules per second which is the same as a 100 watt light bulb. A
newborn only uses about 25 Joules per second. When we run, walk or hurdle this increases our use
of energy. Athletes normally consume much more energy in their diet when they are in training.

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Energy transformations one
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 lost
to the environment. A simple device like a light bulb, for example transfers
e__________ energy to light and h______ energy. Only the light energy is useful
energy, with the heat energy being lost to the environment. Work out the energy
transfers when you a) light a firework, b) digest a Kit Kat & c) Burn wood ?
Energy transformations: Word bank: device electrical heat
Diagram
45 joules of l_____ energy
100 joules of electrical energy
__ joules of heat energy
A light bulb transforms electrical energy into which forms of energy ?
Diagram
___ joules of k_______ energy
1000 joules of electrical energy
700 joules of heat and s________
energy.
A hairdryer transforms electrical energy into which forms of energy ?

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Energy transformations two
Most devices in the home use electrical energy. They are able to transform electrical
energy to other forms including, kinetic, heat, light and sound. Look at the following
examples and complete the table ?
Energy transformations: Word bank: light heat
Diagram
300 joules of l_____ energy
1,000 joules of electrical energy
__ joules of heat energy
A light bulb transforms electrical energy into which forms of energy ?
Diagram
200 joules of l_____ energy
500 joules of electrical energy __ joules of heat energy
100 joules of sound energy
A television transforms electrical energy into which forms of energy ?
Diagram
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 ?

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Energy transformations three
Energy transfer diagrams show the relationship between the input energy and the output energy of a
device 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 electrical
energy to 300 joules of kinetic energy and 200 joules to heat and sound energy. Only the kinetic
energy is useful, with the heat and sound energy being lost to the surroundings. In the following
examples, the useful energy is underlined.
Energy transformations:
Console (100 W) Dyson (500 W) Light bulb (150 W)
Diagram
150W
60W
150 J heat
Transfer
Diagram 50 J sound
Js-1 120 J heat
50 J heat
15 J sound
150 J
100 J 500 J
35 J light 300 J kinetic 30 J light
electrical electrical
electrical
Notes Every second, a games console Every second, a Dyson converts 500 Every second, a light bulb
converts 50 joules of electrical joules of electrical energy into 300 converts 150 joules of electrical
energy into heat, 15 joules into joules of kinetic energy, 50 joules energy into 120 joules of heat
sound and 25 joules into light. into sound and 150 joules into heat. and 30 joules of light energy.
This heat energy is lost to the The heat and sound energy is lost to The heat energy is lost to the
surroundings. the surroundings. surroundings.

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Energy transformations and efficiency
When energy is transformed into another form, some useful energy is lost to the
environment or surroundings. The efficiency of a d_______ can be worked out using
the following formula.
Energy efficiency = Useful energy out/total input energy x 100 (units %)
Energy transformations: Word bank: device
Example Energy in Device Useful energy (red) Energy efficiency
One Calculation:
45 joules of l_____ energy 45 J/100 J x 100
100 J of electrical
= 45%
__ joules of heat energy
Two Work out using the
formula, the energy
7500 kJ of e_______ energy efficiency of a wind
10,000 kJ of kinetic
turbine ?
2500 kJ of heat energy
Three Work out using the
25 kJ of sound & light energy formula, the energy
efficiency of a plasma
100 kJ of electrical
television ?
75 kJ of heat energy

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Conduction
Heat energy can be t___________ by conduction. When materials are heated, the
atoms v_________ more. This kinetic energy can be passed from atom to atom in
conducting materials. Conduction happens in all materials, but in good conductors
like m_________, free electrons can transfer the heat energy more quickly. All metals
are good conductors of heat. Insulators do not have free e__________ and conduct
heat poorly. Explain why metals always feel cold to the touch, whereas wood for
example feels warm ?
Conduction: Word bank: transferred vibrating metals electrons
Conduction Conduction of heat energy
Diagram
Hot Cold
Direction of heat transfer
Notes Heat energy is transferred by vibrating In this picture, heat is conducted and
atoms passing on their kinetic energy to transferred by conduction. Heat energy
adjacent atoms. Metals are good conductors spreads out from the hot or warm regions
because of their free electrons and high (coloured in red) to colder regions
density. (coloured in blue)

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Convection
Heat energy can be transferred through l_________ and gases by convection currents.
Warm gases and liquids are less d________ because their vibrating atoms take up less
space. This means that warm air or liquids rise to the surface. In a hot water tank, the
electric 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 do
not transfer heat energy through solid materials...why ?
Convection: Word bank: liquids dense
Example one Example two
Convection
Diagram
Cold
Hot
Notes As atoms are heated they vibrate more This thermograph The lava lamp first
and occupy more space. The less dense shows how hot made in the 1960s
gases or liquids rise to the top, cool then liquids (coloured in makes use of
sink. Explain why in colds oceans red) rise to the convection currents
nutrients are continuously recycled ? surface in this pot. to produce its effect.

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Radiation
Heat energy from the s____ and other hot objects can be transferred by radiation. This
type of radiation is called infra red radiation and is part of the electromagnetic
spectrum. Infra red radiation can transfer energy through a vacuum and unlike heat
transfer 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 feel
infra red because it has temperature receptors close to its surface. Why has your body
evolved skin that can detected temperature changes ?
Radiation: Word bank: sun conduction
Example one Example two
Radiation
Diagram
10-2m 10-4m 10-6m
e.m. spectrum Infra red
•Travels at 300,000 kms-1
•Transfers energy
•Travels through a vacuum
Notes All hot objects emit infra red radiation. All hot objects The human body is
The Sun is the biggest source of infra red emit heat as infra also a source of infra
radiation. Over 1023 kilojoules of heat red radiation. Does red radiation. Look at
energy falls on the Earth’s surface per year. ice emit infra red ? the above image !

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Sources of energy
There 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 be
combusted 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 was
the original e_______ source. Burning fossil fuels produces carbon dioxide which is
termed a greenhouse gas ...Why ?
Main forms of fossil fuels: Word bank: oil carbon heat energy
Fuel Oil Coal Natural gas
Diagram
Remains of dead insects and Remains of dead plants. Found with crude oil deposits.
Source
other organic material.
Heating, Transport, generating Heating, generating electricity Heating, Generating electricity
Uses:
electricity
Life 60-70 years 300 years 30-40 years
expectancy

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Generating electrical energy from fossil fuels
Combusting fossil fuels like c_____, and natural gas produces h______ energy which
is 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 coil
across a magnetic field induces a c_________ flow in the copper wire. Electrical
energy cannot be stored and is delivered instantly by the National Grid using a
network of overhead wires and underground cables clean and efficiently to every
home in Britain.
Fossil fuels to electricity: Word bank: coal heat current
Fuel Power station Transmission Customer
Diagram
Non-renewable fossil Combusting fossil fuels Electricity is then The amount of electricity
Notes
fuels containing ‘ancient generates large amounts transported along a huge that you use during a
energy’ is extracted of heat energy which in network of underground year is calculated using
from deep underground. turn boils water or over ground copper meter readings. The
These fuels include producing steam. This cables to various users electrical energy can be
crude oil, natural gas drive turbines producing including schools, homes transformed into many
and coal. electricity. and factories. other forms of energy.

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Renewable energy sources
Electricity is very clean at the point of use, but combusting fossil fuels containing
sulphur causes acid rain. Carbon dioxide, another pollutant from burning fossil fuels
traps heat in the atmosphere, therefore causing the g_____________ effect. Many
sources of energy that we currently use every day are now renewable. This means that
unlike coal and natural gas they are not used up. Many scientists are working to
develop 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 Solar Geothermal Biomass Hydroelectric
Diagram
Wind: Wind farms could supply up to 20% of the energy we use every year. Solar: Solar cells using
Notes
solar energy could power traffic lights and street lamps. Geothermal: This type of energy is only
found in certain volcanic areas like Iceland. Biogas: Biogas converts animal waste like manure from
farms into methane using microbes. Hydroelectric: Using moving water, hydroelectric dams are able
to generate clean electricity.

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Hydroelectric power
Hydroelectric dams use water to store g____________ potential energy. When the water is
released 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 impact
of constructing a dam and flooding the valley and surrounding areas is huge. Natural
habitats and local biodiversity are often sacrificed for renewable energy. Not all areas are
suitable for hydroelectricity...explain why ?
Hydroelectric power: Word bank: gravitational clean
Hoover dam Barrage dam Generating electricity using water
Diagram
The Hoover Dam built Great barriers like the Water stored behind the dam is released
Notes
on the Colorado River one picture above are converting gravitational potential energy to
generates over one also used to control kinetic energy and finally electrical energy.
million kilowatts a day flooding and generate What type of weather conditions are required
of clean energy. electricity. to make building dams economic ?

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Biogas and biomass
Biogas or m________ (CH4) is produced by fermenting organic matter like plant and
animal 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 used
as an alternative fuel source in cars. Sugarcane is grown, the sugar is extracted and then
fermented 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: Word bank: methane micobes yeast petrol
Sugarcane Ethanol Animal waste Biogas
Diagram
ethanol
l
a no
et h
Notes Sugarcane is grown using large amounts of Animal waste, like horse manure is used by
land in hot climates. The sugar is converted to bacteria to produce biogas. This is identical
ethanol using yeast. Ethanol performs just as to natural gas. Unlike natural gas which is a
well as petrol and reduces exhaust pollutants fossil fuel, it can be produced over and over
like sulphur and carbon monoxide. again.

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Tidal power
Tides and waves cause local water levels to r______ and fall. A barrage dam traps
w_______ 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 with
hydroelectric dams, flooding can lead to the loss of habitats for many species that live
along river estuaries. Offshore underwater turbines (wave generators) can also use the rise
and 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
Kinetic energy from waves Offshore wave electricity generators
Diagram
Notes Kinetic energy of moving water is Offshore wave generators like those pictured above,
shown by this picture. Wave energy is have little or no impact on the environment unlike
highest during the winter months. barrage dams. The turbine blade is turned by
What causes waves in the seas and moving water, which in turn generates an electric
oceans ? current.

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Geothermal energy
Where the Earth’s crust is thin or where it contains large amount of radioactive substances
like Uranium235 a ready heat source from ‘hot rocks’ is available. Water can be
superheated producing s_______. Inside a geothermal power station, steam turns a turbine
which generates electricity. If the water temperature is lower, it can be used to h______
people’s homes. Iceland has many hot springs and volcanic regions and make use of its
natural geothermal energy. Iceland has so much geothermal energy that residents receive
free heating and electricity for their homes !
Geothermal energy: Word bank: steam heat
Geothermal energy in Iceland Geothermal energy generating electricity
Diagram
Notes The outflow of this geothermal power A natural sources of steam which drives turbines
station in Iceland has become a tourist capable of producing electricity. Pipes that go deep
resort ideal for ‘hot bathing’ It is underground deliver either steam for generators or
known as the blue lagoon. hot water for home heating.

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Renewable wind power
Pressure differences in the Earth’s atmosphere causes winds that blow across countries and
continents. 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 in
turn makes a generator turn. This induces an electric current. Wind generators or farms are
found in w________ places like offshore or in mountainous areas. Although these wind
farms don’t 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
Hurricane Wind farms and inside the wind turbine
Diagram
A single hurricane expends up to 1015 kilo Wind farms are usually located offshore to avoid visual and
Notes
Joules during its short life. The governments noise pollution. Also wind speeds are higher away from
want about 20% of the UK electricity to be land. Wind generators like the one pictured above will be
generated this way. It is clean, renewable used more and more in the future. Each one generates
and relatively cheap. sufficient energy for around 1000 homes.

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Solar power
The Sun is the source of all our energy and each year over 1023 kilojoules of s_______
energy falls on the Earth’s surface. Out total energy consumption per year is around 1021
kJ. Sunlight or solar cells convert solar energy directly to electrical energy. Solar cells are
expensive and only work well on bright sunny days. Also, solar cells cannot produce huge
amounts of electricity for whole towns. They are only useful in remote places, where
cables cannot be laid or for low c__________ appliances like traffic lights.
Solar energy: Word bank: solar current
Solar energy and the Sun Solar cells Solar cooker
Diagram
Sun
Notes Every year, just a small fraction of the Sun’s Solar cells are useful in This cooker uses solar
energy lands on the Earth’s surface. Its value in remote sunny places energy to heat foods to
Kilojoules is 1023 kJ per year. This energy is in a temperature of 200oC.
for very low current
the form of infra red heat and light. About appliances. They are Why is the pot normally
1021kJ joules of this energy is used every year very expensive to painted black and not
by green plants. produce. silver ?

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Cost of electrical energy
In 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 some
sources like solar and n________ power costing much more. Using electricity from
hydroelectric dams and burning fossil fuels like natural gas costs much less. You can
now 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
Wind Solar Biogas Hydroelectric Nuclear Fossil fuels
Diagram
Cost/kWh 4 pence 16 pence 10 pence 2 pence 10 pence 5 pence
Notes: 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 ?

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Energy use in the home
Energy 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. The
lowest demand is during the n________. Power companies use reliable sources of energy like
nuclear 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
Heating Lighting Cooking Other
Diagram
47% 42% 4% 7%
Notes: The percentage of energy used in homes, offices and other building varies over the year. In the
winter the majority of energy is used for home heating and lighting. In the summer there is
less demand because of the warm temperatures and long light evenings.

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Saving energy about the home one
Saving energy makes good sense: It costs you less money, uses up less fossil fuels and
reduces 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. These
innovations help reduce heat e________ escaping through windows, doors, walls and
ceilings. 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
Loft insulation Double glazing Wall insulation Floor insulation
Diagram
About 1500 Joules of Fitting double glazing Insulating the cavities Placing insulation foam
Notes
energy is lost every reduces energy loss by between your walls is underneath carpets, tiles
second through the half from 900 Js-1 to the most effective type or wooden floors
roof. Using insulation 450Js-1. Explain how of insulation, reducing reduces energy loss by
cuts this down to about window double glazing energy lost from 40% from 1200 Js-1 to
500 Js-1. works ? 2,600Js-1 to 1,000 Js-1. 700 Js-1.

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Saving energy about the home two
Saving 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 devices
and 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 are
able to produce the same amount of light. Common sense also plays a large part. Turning
off 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
Light bulbs Turning off lights Boiling less water Wear clothing
Diagram
Energy efficient bulbs At night, in any city or Boiling a full kettle to Indoors, instead of
Notes
use only 12 watts town, count the number make a single cup of turning up the heating
compared to normal of office buildings that coffee wastes energy. you can wear a jumper.
light bulbs which use leave their lights on. Do Many modern kettles Reduce energy wastage
up to 150 watts. Explain you do the same in your can now boil a single by closing doors and
the difference ? own house ? cup. windows.

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Saving energy at home
Earth’s fossil fuels are a finite resource and we can all do ‘our bit’ to reduce the amount of energy
that we consume at home or in the office. New houses are required to be energy e__________ with
loft and wall insulation, efficient gas boilers and double glazing. How we live and respect the Earth’s
resources is important. Just switching off l_______ bulbs, reducing the central heating or not leaving
our 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
Heater (2500W)
(2500 W)
2.5 2,500
Energy use by different devices
Kettle (2000W)
(2000 W)
Heat loss through the roof 2.0 2,000
Hair dryer (1500 W)
(1500W)
1.5 1,500
1500 Js-1
Drill (1200W)
(1200 W)
1.0 1,000
Kilowatts
Watt s Watts
Toaster (900W)
(900 W)
Kilowatts
0.5 500
Laptop (180W)
(180 W)
Light bulb (100W)
(100 W)
0.0 0
Heat loss
through windows
900 Js-1
Heating
Heat loss
Picture to the left is how energy is used and lost in
Lighting through wall
an average home. Using the information above,
2600 Js-1
work out how you can save energy at home. Think
how you can save energy used for lighting and
1200 Js-1
heating. Also how can you reduce heat loss in
your home, through the walls, windows, roof
space and floors ?
Heat loss though the floor

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Cars of the future ?
Using h__________ fuel cells in cars and buses as an alternative to using petrol and diesel
is now a real possibility. In 2003 London Buses took delivery of four buses than run using
the 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
Hydrogen fuel cell How it works Hydrogen car
Diagram
Notes Hydrogen and oxygen A current drives an The car of the future ? Imagine your
fuses together forming electric motor producing exhaust emitting only water. Not just
water as a waste liquid and movement. The surplus a distant dream but soon a reality
power in the form of energy can be stored in a when the costs of design and
electricity. battery. manufacture comes down.

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Extension questions and homework
1: Define the following terms: Energy, Device, Joule, Kilo-joules, Fossil-fuels, Efficiency & Renewable.
2: Look at the three pictures below. Complete the table.
Hot Cold
Direction of heat transfer
Transfer method Examples How is energy transferred ?
Conduction
Convection
Radiation
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.

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4: Look at the information in the table below. Answer the questions:
Insulating method Initial cost Saving each year Cost effectiveness
Double glazing Expensive (£8000) Low (£150) Low
Loft insulation Inexpensive (£450) High (£250) High
Wall insulation Moderately expensive (£2450) High (£195) High
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) Geothermal
energy.
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.