AQA GCSE Physics Energy KnowIT PDF

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KnowIT! Energy changes and energy stores Part 1 Energy stores and systems Energy stores and systems An energy system is a group of objects that have the ability to Remember: do work. energy can not be created or destroyed so when work is done, energy from one store is carried along a pathway to another energy store. Consider the energy flow diagram for an electric shaver. The battery has a store of chemical energy. The current flows through an electrical pathway to the motor. Energy from the motor follows a mechanical pathway to a kinetic store of the moving blades, a heat pathway to a thermal store and a radiation pathway to Mot a sound store. mechanical Kinetic or electrical Chemical heat Energy stores and systems Energy stores Examples Chemical In food, fuel and electric batteries Kinetic In moving objects Gravitational In objects raised above a planets potential surface In a stretched, compressed or twisted Elastic potential object Internal (thermal) In any heated object Magnetic In any object with a magnetic field Electrostatic In electrostatic forces between charges The forces acting between atomic Nuclear nuclei Force pathways include: Mechanically – when a force acts and an object moves Electrically – when an electric current flows Energy stores and systems Examples of energy changes in a system: An object thrown (projected) upwards e.g. You throw a tennis As theball upwards. ball leaves your hand it has a store of kinetic energy. At its highest point it has a store of gravitational potential energy (G.P.E). As you are about to catch it just before it hits your hand it has a store of kinetic energy. A moving object hitting an obstacle e.g. A bowling ball As you move the muscles of your arm to throw the ball the hitting a pin chemical energy store in your muscles decreases and the kinetic energy store of the bowling ball increases. At the ball hits a pin some of the kinetic energy has been transferred to a store of internal (thermal) energy this causes the ball and its surroundings to warm up a little. You will hear a sound when the ball hits the pin, the energy of the sound is also transferred to the internal energy store of the surroundings. Energy stores and systems Examples of energy changes in a system: A vehicle slowing down e.g. When you apply the brakes in a lorry The moving lorry has a store of kinetic energy. At the brakes are applied the kinetic energy store decreases the energy is transferred to the internal (thermal) energy store in the brakes and the brakes get hot. You will hear a sound when the brakes of the lorry are applied, the energy of the sound is also transferred to the internal energy store of the surroundings. When the lorry stops its kinetic energy store is zero. Bringing water As the fuel to the burns a boil on a camping chemical energy stove. store in the fuel decreases and the internal (thermal) energy store of the water increases. The temperature of the water increases and as bubbles form the kinetic energy store of the water increases. Energy is measured in Joules (J) 1 kilojoule (kJ) = 1000 J (103J) 1 megajoule = 1000 6 Energy stores and systems Energy change – mechanical work is the amount of energy transferred by a force When a pushback truck is used to move an aircraft, it does work. Work (J) = Force (N) x Distance (along the line of the force) (m). W=Fs If the aircraft has a mass of 30 000kg and it is moved a distance of 20m, calculate the work done by the pushback truck. Force (weight) = mass x gravitational field strength Force = 30 000 x 10 = 300 000 N W=F s Work = 300 000 x 20 = 6 000 000 J (6 MJ) Energy stores and systems Energy change – Electrical work is done when charge flows in a circuit is the amount of energy transferred. When a current flows through a circuit, work is done (energy is transferred) and the energy store changes. Energy transferred (Work) (J) = Charge flow (Q) x Potential difference (V) E=QV In one minute, 30 Coulombs of charge flows through the bulb when a potential difference of 3 V is placed across it. Calculate the work done (energy transferred). E=QV E = 3 x 30 Energy transferred (Work) = 90 J Changes in Energy - Kinetic Energy Moving objects have kinetic energy. The long-jumper is using her kinetic energy to carry her body as far as possible. The more kinetic energy she has, the longer her jump will be. Her kinetic energy depends on her mass (which she can not change) and her velocity (she can run faster!). Changes in Energy - Elastic Energy Stretched or bent objects have elastic energy (Ee) if they have the ability to recover to their original shape and dimensions. When a weight (force) is added to a spring it extends (gets longer). The spring now has a store of elastic potential energy The which amount ofwill be released stored if the weight elastic energy (Ee) canisbe removed. calculated using the following equation: Elastic potential energy (J) = 0.5 × Spring constant (N/m) × Extension2 (m) Ee = ½ k e 2 In the above example the spring has a spring constant of 670 N/m. The elastic potential energy of the spring when a 50 N load is hung from it is: Ee = ½ k e 2 Ee = 0.5 x 670 x 0.0752 The elastic energy stored in the spring is: Ee = 1.88 J Changes in Energy – Gravitational potential energy When an object is raised above ground level it gains gravitational potential energy (GPE). This stored energy can be released if the object is allowed to fall. A pile driver is a machine that lifts a heavy The amount weight of gravitational then drops potential it on a post to driveenergy it into (G.P.E) the gained by an object raised above ground level can be calculated using the ground. equation: G.P.E (J) = Mass (kg) × Gravitational field strength (N/kg) × Height (m) Ep = m g h The pile driver hammer has a mass of 120 kg and it is raised to a height of 4 m above the ground. How much G.P.E will it have? Ep = m g h Ep = 120 x 10 x 4 The G.P.E gained is: Ep = 4800 J Questio nIT! Energy changes and energy stores Part 1 Energy stores and Energy systems part 1– AnswerIT 1. What sort of energy store do the following examples have? a. b. c. 2. Write down the correct answer to complete the statement. Energy can not… be transferred from one source to another. be created or destroyed. travel along a pathway to another store. 3. A basketball player throws the ball into the hoop. Describe the Energy stores and Energy systems part 1– QuestionIT 4. Copy and Complete the energy store and pathway diagrams for the objects described. a. A moving car braking to a stop. CAR b. Bringing water to the boil on a gas hob. Energy stores and Energy systems part 1 – QuestionIT 5. Describes the main change in energy stores for a coal fired power station. a. Name the energy sources for: i Input energy ii Useful output energy iii Wasted output energy. b. In one hour, coal supplies 500 000 J of energy. The wasted energy amounts to 380 000 J. Calculate how much useful energy is produced in one hour. Energy stores and Energy systems part 1 – QuestionIT 6. When a football is kicked it gains kinetic energy. a. What is the formula used to calculate kinetic energy? b. The football has a mass of 0.4 kg. When the football is kicked, it has a velocity of 15 m/s. Calculate the kinetic energy of the moving football? 7. The un-stretched spring opposite has a length of 0.5 m but after a mass is added it is 0.6 m long. If the spring constant is 800 N/m. Calculate the stored elastic potential energy. Ee = ½ k e2 Energy stores and Energy systems part 1 – QuestionIT 8. A pole vaulter just clears the bar which is 5.1 m high. His mass is 62 kg. (g = 10N/kg) a. What type of stored energy does he have as he just clears the bar? b. Work out how much stored energy the pole vaulter has due to his position above the ground. c. As he falls back to the ground, this energy store will be transferred into a new energy store. Name this new energy store. AnswerI T! Energy changes and energy stores Part 1 Energy stores and Energy systems part 1– AnswerIT 1. What sort of energy store do the following examples have? a. b. c. Chemical Elastic potential Thermal 2. Write down the correct answer to complete the statement. Energy can not….. be transferred from one source to another. be created or destroyed. travel along a pathway to another store. Energy stores and Energy systems part 1– QuestionIT 4. Copy and Complete the energy store and pathway diagrams for the objects described. a. A moving car braking to a stop. CAR i Kinetic ii Mechanical iii Thermal b. Bringing water to the boil on a gas hob. i Chemical GAS HOB ii Heating iii Thermal Energy stores and Energy systems part 1 – QuestionIT 5. Describes the main change in energy stores for a coal fired power station. a. Name the energy sources for: i Input energy Chemical (Coal) ii Useful output energy Electrostatic (Electric current) iii Wasted output energy. Thermal (Waste heat) b. In one hour, coal supplies 500 000 J of energy. The wasted energy amounts to 380 000 J. Calculate how much useful energy is produced in one hour. Energy stores and Energy systems part 1 – QuestionIT 6. When a football is kicked it gains kinetic energy. a. What is the formula used to calculate kinetic energy? Ek = ½ m v2 b. The football has a mass of 0.4 kg and when kicked has a velocity of 15 m/s. Work out the kinetic energy of the moving ball? Ek = ½ x 0.4 x 152 Ek = 45 J 7. The un-stretched spring opposite has a length of 0.5m but after a mass is added it is 0.6 m long. If the spring constant is 800 N/m. Calculate the stored elastic potential energy. Ee = ½ k e2 Energy stores and Energy systems part 1 – QuestionIT 8. The pole vaulter just clears the bar which is 5.1 m high. His mass is 62 kg. (g = 10N/kg) a. What type of stored energy does he have as he clears the bar? gravitational potential energy b. Work out how much stored energy the pole vaulter has due to his position above the ground. GPE = m g h = 62 x 10 x 5.1 = 3162 J c. As he falls back to the ground, this energy store will be transferred into a new energy store. Name this new energy store. kinetic energy LearnI T! KnowI T! Energy changes and energy Energy changes in systems The thermal (internal) energy store in a system changes if its temperature changes. When metal is heated in a furnace the thermal energy store increases. The amount of energy gained depends on the mass of the metal, how much the temperature increases and the specific heat capacity of the metal. Specific Heat Capacity ( c ) – the amount of energy required to raise the temperature of 1 kg of a substance by one degree Celsius. Steel has a specific heat capacity of 450 J/kg oC Therefore a 1 kg block of steel needs 450 J of thermal energy adding to it to raise the temperature from 20 oC to 21 oC (1 oC rise). Energy changes in systems and power Specific heat capacity The apparatus shown can be used to determine the specific heat capacity of aluminium. Example: When the heater was left on for 5 mins, the heater supplied 10 800 J of thermal energy to the aluminium block. The temperature of the 2 kg block of aluminium rose by 6 oC. The amount of energy stored in or released from a system as its temperature changes can be calculated using the equation: Change in thermal energy (J) = Mass (kg) x Specific Heat Capacity J/kg oC x Temperature Change (oC) ΔE = m x c x Δθ rearrange to give c = ΔE / m x Δθ c = 10 800 / 2 x 6 Specific heat capacity of aluminium = 900 J/kg oC Power Power - the rate at which energy is transferred the rate at which work is done (rate means “how quickly”) Power is measured in Joules / second 1 J/s = 1 Watt An object which transfers energy does so at a certain rate. The metal filament in this light bulb transfers the electrical energy store into heat and light. This bulb Power transfers can be 2400 calculated usingjoules of energy the following in 60 equation: seconds. Power (W) = Energy transferred (J) Time (s) P=E P= 2400 / 60 = 40 J/s t So this is a 40 Watt light bulb. Power Power - the rate at which energy is transferred the rate at which work is done (rate means “how quickly”) Mechanical power Power = work done / time The crane lifts the 2000 kg container through a height of 5.4m in 30s. The power of the crane is: Power = Work / time But: Work = force x distance = 20 000 N x 5.4 m = 108 000 J Power = 108 000 J / 30 s Questio nIT! Energy changes and energy stores Part 2 Energy changes in Energy stores and Energy systems part 2 – QuestionIT 1. The specific heat capacity of a substance is…...... A. the ability of a 1 kg object to store transferred energy B. the total amount of stored energy in an object C. the energy needed to raise the temperature of 1 kg of a substance by 1 oC. 2. When a bowl of water and a stone are left in hot sunshine, the stone feels much hotter than the water. Which one has the highest specific heat capacity? Explain your answer. 3. Give two alternative units of power? Energy stores and Energy systems part 2 – QuestionIT 4. A blowtorch burns butane gas to heat metal pipes. a. Describe the energy transfers which occur as it is used. energy is transferred into energy usefully and energy is wasted. b. Explain how some of the transferred energy is wasted. c. The blowtorch transfers 2 kJ of energy in 4 mins. Work out the power of the blowtorch? Energy stores and Energy systems part 2 – QuestionIT 5. Two cranes are lifting the same load of 120 kg to a height of 15 m. Crane A Crane B Crane A takes 30 s to lift the load. Crane B lifts the same load in 9 s. Calculate the difference in power of the two cranes. Energy stores and Energy systems part 2 – QuestionIT 6. Storage heaters contain bricks which warm up and store the heat energy. The bricks in this heater have a mass of 40 kg and are heated from 18 oC to 40 oC. If the specific heat capacity of the brick material is 850 J/kg oC. Calculate the change in thermal energy during heating. Change in thermal energy = Mass x Specific Heat Capacity x Temperature Change ΔE = m x c x Δθ AnswerI T! Energy changes and energy stores Part 2 Energy changes in Energy stores and Energy systems part 2 – AnswerIT 1. The specific heat capacity of a substance is …........ A. the ability of a 1kg object to store transferred energy B. the total amount of stored energy in an object C. the energy needed to raise the temperature of 1kg of a substance by 1oC 2. When a bowl of water and a stone are left in hot sunshine, the stone feels much hotter than the water. Which one has the highest specific heat capacity? Explain your answer. The water has a higher heat capacity as it takes more heat energy to raise its temperature to that of the stone 3. Give two alternative units of power? Energy stores and Energy systems part 2 – AnswerIT 4. A blowtorch burns butane gas to heat metal pipes. a. Describe the energy transfers which occur as it is used. Chemical energy is transferred into thermal energy usefully and light energy is wasted. b. Explain how some of the transferred energy is wasted. As thermal energy to the environment c. The blowtorch transfers 2 kJ of energy in 4 mins. Work out the power of the blowtorch? Power = energy transferred / time = 2000 / 240 Energy stores and Energy systems part 2 – AnswerIT 5. Two cranes are lifting the same load of 120 kg to a height of 15 m. Crane A Crane B Crane A takes 30 s to lift the load. Crane B lifts the same load in 9 s. Calculate the difference in power of the two cranes. Crane A power = 1200 x 15 / 30 = 600 W Crane B power = 1200 x 15 / 9 = 2000W Energy stores and Energy systems part 2 – AnswerIT 6. Storage heaters contain bricks which warm up and store heat energy. The bricks in this heater have a mass of 40 kg and are heated from 18 oC to 40 oC. If the specific heat capacity of the brick material is 850 J/kg oC, calculate the change in thermal energy during heating. Change in thermal energy = Mass x Specific Heat Capacity x Temperature Change ΔE = m x c x Δθ temperature change Δθ = 40 – 18 = 22 oC change in thermal energy ΔE = 40 x 850 x 22 ΔE = 748 000 J or 748 kJ LearnIT! KnowIT! Conservation and Dissipation of Energy Energy transfers in a system Energy transfers in a system Energy can be stored, transferred or dissipated - but can not be created or destroyed. No mass In a closed change In a closed energy system energy there can be Close system all transfer of E in d E the energy energy but not Energ out can be mass. There is y accounted for no change to syste even when m the total energy stores energy in the The diagram shows the energy transfer change. for a system. light bulb. All the electrical energy store can be accounted for as light energy and thermal energy. The thermal energy is not useful in this case Energy transfers in a system Unwanted energy transfers result in energy stores that are not useful. The F1 car below shows that eventually all the chemical energy (fuel) put in the car ends up as unwanted thermal energy which is dissipated to the surroundings. Unwanted energy is often described as being ‘wasted’ Kineti Therm Chemi c al cal Sound Therm Therm al al Kinetic energy is dissipated by the tyres, brakes and air resistance to become unwanted thermal energy stores. Sound energy is absorbed by materials and becomes thermal energy. Thermal energy is produced by the engine as fuel is Energy transfers in a system Thermal insulation is often used to reduce unwanted energy transfers. All the energy used to heat a home is eventually transferred as thermal energy to the surroundings. The diagram, shows the percentage Thermal energy lost through Conductivi Material The higher the thermal conductivity, the differentW/m parts ty C of the building. quicker heat is transferred through the 0.03 Air Polyureth 0.03 material. Houses are often built from brick, ane foam Fibreglass 0.04 concrete, wood and glass. All have quite 0.05 Wool felt Wood 0.15 high thermal conductivity values. Plaster 0.50 Insulation uses materials with low Glass 0.80 Brick 1.00 thermal conductivity, such as fibreglass Concrete 1.04 in the loft, foam in wall cavities and Efficiency The amount of useful energy you get from an energy transfer, compared to the energy put in, is called the EFFICIENCY Efficiency = useful output energy This calculation will resul in a decimal value which transfer total input can be multiplied by 100 energy transfer to give a percentage efficiency. A wind turbine energy The wind turbine produces 120 transfer MW of electrical energy for every 500 MW of kinetic energy provided by the wind. Efficiency = Useful output energy transfer total input energy transfer = 120 = 0.24 efficient 500 Efficiency Efficiency can also be calculated from the power transferred. Efficiency = useful power Remember that power is output the time it takes to do total work. A water power input pump lifting Work = Force x distance water The 300 W water pump raises 200 kg of water to a height of 2 m in one minute. The efficiency of the pump is: Efficiency = useful power output total power input Power in = 300 W Power out = 2000 N x 2 m = 66.7 W Questio nIT! Conservation and Dissipation of Energy Energy transfers in a system Conservation and Dissipation of Energy - QuestionIT 1. In a “closed” system ….......... A. energy can be transferred but there is no net energy loss. B. energy and mass are transferred in and out of the system. C. energy cannot be transferred between different energy stores. 2. The energy transfer diagram for a mobile phone shows that 100 J of electrical energy produces 45 J of light energy and 36 J of sound energy. How much thermal energy will be dissipated by the phone? Conservation and Dissipation of Energy - QuestionIT 3. Describe how the thermal energy produced by a bus driving along a road is dissipated. 4. a. The diagram shows the main energy transfers for an electric fan. Complete boxes A to D showing the energy stores involved. Use the size of the arrows to help you. B A C D b. State why the total energy supplied an electric fan must always equal the total energy transferred by the electric fan. Conservation and Dissipation of Energy 5. a. The diagrams show two different - QuestionIT types of loft insulation. Fiberglass insulation Wool insulation The wool needs to be thicker to have the same insulating properties. Explain which material has the highest thermal conductivity? b. Explain how trapped air reduces the rate of heat loss, in terms of thermal conductivity. Conservation and Dissipation of Energy - QuestionIT 6. The diagram represents the energy store transfers when a motor is lifting a weight. Electrica Gravitational l energy potential 340 J energy 100 J Therma Sound 80 l? J a. How much electrical energy is transferred to a thermal energy store? b. What is the total amount of dissipated energy? c. Calculate the efficiency the of the useful energy transfer Conservation and Dissipation of Energy - QuestionIT 7. The motor for a lift in a tall building uses 12 000 W of power. The lift and its passengers has a mass of 500 kg. The lift motor takes 10 s to raise the lift and its passengers through a height of 20 m. Work out the percentage efficiency of the lift motor. 8. The low energy bulb below uses 18 000 J of energy in one hour. If the efficiency of the low energy bulb is 78 %. Work out the amount of light energy given off by the bulb AnswerI T! Conservation and Dissipation of Energy Energy transfers in a system Conservation and Dissipation of Energy - AnswerIT 1. In a “closed” system ….......... A. energy can be transferred but there is no net energy loss. B. energy and mass are transferred in and out of the system. C. energy cannot be transferred between different energy stores. 2. The energy transfer diagram for a mobile phone shows that 100 J of electrical energy produces 45 J of 45 J + 36 J = 81 J light energy and 36 J of sound energy. How much thermal energy will be dissipated 100 J by the – 81 J = 19 phone? J 19 J of thermal energy will be dissipated Conservation and Dissipation of Energy 3. Describe how the thermal energy - AnswerIT produced by a bus driving along a road is dissipated. The thermal energy increases the kinetic energy of the air particles therefore warming up the surroundings. 4. a. The diagram shows the main energy transfers for an electric fan. Complete boxes A to D showing the energy stores involved. Use the size B of the A arrows to help - Electrical you. energy B - Thermal energy A C C - Kinetic energy D D - Sound energy b. State why the total energy supplied to an electric fan must always equal the total energy transferred by the electric fan. Energy can not be created or destroyed so: total energy in = total energy out Conservation and Dissipation of Energy - AnswerIT 5. a. The diagrams show two different types of loft insulation. Fiberglass insulation Wool insulation The wool needs to be thicker to have the same insulating properties. Explain which material has the highest thermal conductivity? Wool has the highest thermal conductivity as it lets thermal energy through at a faster rate so a thicker layer is needed for the same insulation as the fiberglass. b. Explain how trapped air reduces the rate of heat loss, in terms of thermal conductivity. The air trapped inside the fiberglass acts as an Conservation and Dissipation of Energy - AnswerIT 6. The diagram represents the energy store transfers when a motor is lifting a weight. a. How much electrical energy is transferred to a thermal energy store? 340 – (100 + 80) = 160 J b. What is the total amount of dissipated energy? 160 + 80 = 240 J c. Calculate the efficiency the of the useful energy transfer Efficiency = useful output energy transferred = 100 = 0.294 Conservation and Dissipation of Energy - QuestionIT 7. The motor for a lift in a tall building uses 12 000 W of power. The lift and its passengers has a mass of 500 kg. The lift motor takes 10 s to raise the lift and its passengers through a height of 20 m. Work out the percentage efficiency of the lift motor. Efficiency = power out x 100 Power out = work work = force x distance power in time Power out = 5000 N x 20 m = 10 000 W Efficiency = 10 000 x 100 = 83 % 10 s 12 000 8. The low energy bulb below uses 18 000 J of energy in one hour. If the efficiency of the low energy bulb is 78 %. Work out the amount of light energy given off by the bulb in one hours. Efficiency = energy out x 100 energy out = efficiency x energy in LearnIT! KnowIT! National and Global Energy resources National and global energy resources ENERGY RESOURCES Non-renewable Coal Fossil fuels Oil They are becoming more difficult to find and extract Gas Nuclear Plentiful but difficult to extract / purify Renewable Bio-fuel Plant matter usually used as a fuel Wind Turbines spin a generator to produce electricity Hydro-electric Falling water spins a turbine to produce electricity Geothermal Hot rocks underground produce steam Tides Rise and fall of the tide can be used to turn a turbine Sun To directly heat things or produce electricity Waves Up and down movement can turn turbines National and global energy resources Non-renewable energy sources are those which will eventually run out – there is a finite supply. New supplies are more difficult to find and extract. Renewable energy sources are those which can replenish themselves in the short term, and so will never run out. Nuclear energy resources are technically non- renewable but they can be produced on an almost How energy indefinite resources are used. basis. Transport – cars, trains, buses, planes etc. Electricity generation – industry, homes, commerce, lighting etc. Heating – homes, industrial processes, schools and hospitals etc. Energy use is usually divided between the four Energy resources – Non-renewable Coal Coal is mined Large reserves Coal mining is then burnt to of coal which dangerous and burning coal provide heat are relatively contributes to global or used to inexpensive to warming. generate mine. electricity. All major coal mines have now closed in the UK. Oil Frequently burnt Large reserves Oil reserves to produce becoming more becoming more electricity. Large difficult to find and difficult to find and quantities of oil extract. Transport extract. are refined to and refinement are The need for oil in provide fuels for relatively easy. developed countries transport. means supplies are politically sensitive. Releases greenhouse gases when burnt. Energy resources – Non-renewable Gas Extracted from Cleaner than UK has good gas underground gas burning oil or reserves but extraction is expensive (often fields sometimes coal. under the sea) and alongside oil Relatively becoming more difficult extraction. Mainly easy to to reach. used for electricity transport and production, store. domestic heating and industrial processes that require heat. Nuclea Nuclear supplies Potentially in- Danger of nuclear r (Uranium) are mined exhaustable accidents releasing and purified. The energy supply radioactive materials nuclear fission even though it is into the air or water. releases heat which is extracted form Security of nuclear used to produce resources in the sites can be a steam. This spins a ground.Very problem.Start-up costs turbine and generator efficient process and decommissioning to make electricity which produces are very expensive and lots of electricity no real solution to Energy resources – Renewable Solar Energy from Renewable Manufacture and sunlight is energy installation of solar panels/cells can be captured in resource. costly. photovoltaic cells Individual and converted into houses can electricity. have their own Hot water from electricity/hot solar panels water supply. Wind Wind turbines turn Renewable Manufacture and wind energy into energy resource installation of wind electricity by turning a and can be used farms can be generator. as individual costly. units. Some consider an eyesore. Tidal The movement of Ideal for an island Construction of tides drives turbines. such as the UK to barrage is very A tidal barrage is built potentially costly and can across estuaries generate a lot of impact on wildlife. to trap water. energy. Only a few Tidal barrage can estuaries are help prevent suitable. Energy resources – Renewable Geothermal In volcanic Renewable Can be regions, cold energy expensive to set up and only water is pumped resource. works in areas underground and Used of volcanic comes out as successfully in activity. steam. Steam can some be used for countries, heating or to such as New power turbines Zealand and creating Iceland. electricity. Hydroelectri Energy harnessed Creates water Costly to build. c Power from the movement of reserves as well Can cause the (HEP) water through rivers, as energy flooding of lakes and dams. Used supplies. surrounding to turn turbines for communities electricity production. and landscapes. Energy resources – Renewable Biomass An organic It is a cheap When burned, it material, which and readily gives off greenhouse can be burned to available gases. provide energy, eg source of Growing takes heat or electricity. energy. up large After treatment If replaced, amounts of with chemicals it biomass can arable land.. can be used as a be a long- fuel in vehicle term, engines. sustainable energy source. Wave The movement of More likely to be Construction water in and out of a small local can be costly. cavity on the shore operations, Only produces compresses trapped rather than done small amounts air, driving a turbine. on a national of electricity. scale. National and global energy resources Security and reliability of energy supplies e y In the UK a mix of energy supplies are h T rg used so should one supply become n e ix E m unavailable, others can be used without disruption to supplies. Some energy sources are more reliable than others. Coal, oil, gas and nuclear are reliable sources as they can supply a continuous flow of electricity. Electricity from wind turbines relies on the wind blowing, solar power does not work at night and hydro-electric requires a continuous supply of water. These are considered unreliable sources. National and Global energy resources – Trends in energy use World energy use trends and predictions The total amount of energy used in the world is increasing as the population increases and each person is using more energy. Renewable energies only make up around 20% of total energy consumption and this trend is unlikely to Future world agreements on emissions are change until after 2035. likely to determine the trend of using fossil fuels. As reserves of coal, oil and gas dwindle, an increase in the use of renewable energies is Questio nIT! National and Global Energy resources National and Global Energy resources – QuestionIT 1. What is a fossil fuel? 2. Copy and complete the table below by ticking the correct box for Energy each energy source source. Renewable Non-renewable Bio-fuels Oil Nuclear Hydro-electricity Wind turbines Coal Solar power Wave energy Natural gas 3. What is a renewable energy source? National and Global Energy resources – QuestionIT 4. Why are fossil fuels considered to be a more reliable energy resource than renewable energy resources? 5. Despite a large investment by the UK government in wind power, the amount of fossil fuel used has not seen a decline. Give a possible explanation for this. 6. The UK government is committed to investing in a "blend" of energy supply types to provide the UK’s energy needs for the next 100 years. Give an advantage of this rather than using National and Global Energy resources – QuestionIT 7. The graph shows the world use of renewable energies over the past sixty years. a. Why has the use of wood increased very little over this time? b. A lot of money has been invested in wind turbines. Why does this energy source not produce as much as any other renewable resource? National and Global Energy resources – QuestionIT 8. Copy and complete the table to give energy sources that could be used Energy in eachuse situation. Energy Energy source 1 source 2 Running a car Producing electricity Heating the home Powering a train 9. Describe how human activities have contributed to the greenhouse effect? National and Global Energy resources – QuestionIT 10. Explain how burning coal in power stations contributes to global warming. 11. Describe two problems associated with the storage of waste from nuclear power stations. 12. State two reasons why people might object to having a wind farm built close to their homes. AnswerI T! National and Global Energy resources National and Global Energy resources – AnswerIT 1. What is a fossil fuel? A fuel formed in the geological past from the remains of living organisms. 2. Copy and complete the table below by ticking the correct box Energy for source Renewable Non-renewable Bio-fuels each energy source. Oil Nuclear Hydro-electricity Wind turbines Coal Solar power Wave energy Natural gas National and Global Energy resources – AnswerIT 4. Why are fossil fuels considered to be a more reliable energy resource than renewable energy sources? Produce a consistent energy supply with no gaps in energy delivery. 5. Despite a large investment by the UK government in wind power, the amount of fossil fuel used has not seen a decline. Give a possible explanation for this. UK is using more energy and wind power can not meet this rise in demand. 6. The UK government is committed to investing in a "blend" of energy supply types to provide the UK’s energy needs for National and Global Energy resources – AnswerIT 7. The graph shows the world use of renewable energies over the past sixty years. a. Why has the use of wood increased very little over this time? Limited supplies of wood and it takes a long time to grow new supplies. Also, pressure and legislation to prevent many trees from being cut down. b. A lot of money has been invested in wind turbines. Why does this energy source not produce as much as any other renewable resource? National and Global Energy resources – AnswerIT 8. Copy and complete the table to give energy sources that could be used in each Energy use situation. Energy source 1 Energy source 2 Running a car Petrol, Diesel, Any electricity LPG producing source Producing Coal, oil, gas Renewable source electricity Heating the home Coal, gas, wood Any electricity producing source Powering a train Coal, Diesel, oil Any electricity producing source 9. Describe how human activities have contributed to the greenhouse effect.? Burning fossil fuels for heating, transport and National and Global Energy resources – AnswerIT 10. Explain how burning coal in power stations contributes to global warming. Carbon dioxide produced. Carbon dioxide absorbs and reflects infrared radiation leading to additional warming. 11. Describe two problems associated with the storage of waste from nuclear power stations. Waste is radioactive can cause cells to mutate. Radioactivity lasts for thousands of yeas so needs long term storage. 12. State two reasons why people might object to having a wind farm

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