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GCSE PPaper1 > Energy (1)- pt 2 > Flashcards

Energy (1)- pt 2 Flashcards

1
Q

Explain how radiators create convection currents

A
  • Energy transfers from the radiator to nearby air particles by conduction (air particles collide with the radiator surface)
  • air nearer the radiator becomes warmer and less dense
  • warm air rises and is replaced by cool air, which is heated by the radiator
  • the previously heated air transfers energy to the surroundings. It cools becomes denser and sinks
  • the cycle repeats
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2
Q

What reduces unwanted friction between the surface of 2 objects?

A
  • Lubricants

- usually liquids (like oil) that can flow easily between objects and coat them

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3
Q

What reduces unwanted air resistance?

A

Streamlining an object

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4
Q

How could you prevent energy loss through heating?

A
  • thick walls, made of materials with a low thermal conductivity.
  • use thermal insulation
  • reducing the difference between the temperature inside and outside the house
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5
Q

Give 4 examples of thermal insulation

A
  • cavity walls: an air gap between 2 walls. This reduces conduction. If it has foam in the gap it’ll reduces convection.
  • loft insulation reduce convection currents being created in lofts
  • double-glazed windows: an air gap between 2 sheets of glass. Prevents conduction
  • draught excluders around doors and windows reduce convection
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6
Q

What makes ‘useful devices’ useful?

A

Because they can transfer energy from one store to another

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7
Q

What are the 2 equations for finding efficiency?

A

Efficiency=useful output of energy transfer/ total input energy transfer
Efficiency=useful power output/total power input

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8
Q

…….. device is 100% efficient, the wasted energy is usually transferred to useless …….. energy stores

A

No

Thermal

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9
Q

What 1 exception is there to the rule ‘no device is 100% efficient’?

A

Electric heaters- they’re usually 100% efficient because all the energy in the electrostatic energy store is transferred to ‘useful’ thermal energy stores.

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10
Q

What are non-renewable energy resources?

A
  • fossil fuels and nuclear fuel (uranium and plutonium).
  • which provide most of our energy
  • natural resource that form underground over millions of years
  • burnt to provide energy which damages the environment
  • will run out eventually
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11
Q

List the 3 main fossil fuels?

A
  • coal
  • oil
  • (natural) gas
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12
Q

What are renewable energy resources?

A
  • they will never run out
  • most do damage the environment, but not as badly as non-renewables
  • they don’t provide much energy and some of them are unreliable because they’re weather dependant.
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13
Q

List all 7 renewable energy resources?

A
  • the sun (solar)
  • wind
  • water waves
  • hydro-electricity
  • bio-fuel
  • tides
  • geothermal
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14
Q

How are non-renewable energy resources used in transport?

A
  • petrol and diesel powered vehicles (including most cars)use fuel created from oil
  • coal is used in some old-fashioned steam trains to boil water to produce steam
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15
Q

How are renewable energy resources used in transport?

A

-Vehicles that run on pure bio-fuels or a mix of a bio-fuel and petrol or diesel. (Only the biofuel is renewable though)

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16
Q

How are non-renewable energy resources used for heating?

A
  • natural gas is used the most for heating homes in the uk. The gas is used to heat water, which is then pumped into radiators throughout the home.
  • coal is commonly burnt in fireplaces
  • electric heaters (/storage heaters) use electricity generated from non-renewable energy resources
17
Q

How are renewable energy resources used for heating?

A
  • a geothermal (/ground source) heat pump uses geothermal energy resources to heat buildings
  • solar water heaters work by using the sun to heat water which is then pumped into radiators in the building
  • burning bio-fuel/using electricity generated from renewable resources can also be used for heating
18
Q

Explain how we can use wind power

A
  • they need exposed places like on moors or coasts.
  • Each turbine gas a generator inside which produces electricity
  • it doesn’t pollute (except a bit when it’s manufactured)
  • you need 1500 wind turbines to replace 1 coal fired power station which would cover a lot of ground
19
Q

What are disadvantages of using turbines?

A
  • Visual pollution
  • can be noisy which can annoy people living near by
  • weather dependant
  • initial costs are quite high but there’s no fuel costs and minimal running costs
  • no permanent damage to the landscape
20
Q

Explain how solar cells work

A
  • generate electric currents directly from sunlight
  • good for things don’t require much electricity like calculator and watches
  • often used in remote places (Australia outback)
21
Q

Explain some advantages and disadvantage of solar cells

A
  • there’s no pollution (although a lot of energy in required when it’s being manufactured)
  • can be a reliable source-but only in the day. It can still be cost-effective in cloudy countries
  • like wind you can’t increase the power output when there’s extra demand
22
Q

Explain how geothermal power works and it’s advantages and disadvantages

A
  • used in volcanic areas or areas with hot rocks. It due to the slow decay of radioactive elements (eg. Uranium)
  • it’s free, reliable and does little damage to the environment
  • can be used to generate electricity or heat buildings
  • but there aren’t many suitable locations for power plants and the cost of building one is high compared to the amount of energy it produces
23
Q

Explain how hydro-electric power works? And what are it’s advantages?

A
  • requires flooding of a valley by building a dam then water is allowed through turbines
  • there’s no pollution
  • can provide immediate response to an increased demand for electricity
  • there’s no problem with reliability except if there’s a drought
  • initial costs are high but there’s no fuel cost and minimal running cost
  • useful on a small scale in remote areas
24
Q

What are the disadvantages of hydro-electric power?

A
  • has a big impact on the environment due to the flooding of the valley (rotting vegetation releases methane and CO2)
  • The loss of habitats for some species
  • reservoirs can also look ugly when they dry up
25
Q

What is wave power? And what the advantages and disadvantages of it?

A
  • they’re wave powered turbines located around the coast. The moving turbines are connected to a generator
  • doesn’t pollute. Fairly unreliable, waves die out when the wind drops
  • and disturbs the seabed and the habitats or marine animals, spoiling the view and are a hazard to boats
  • initial costs are high, but there are fewer any fuel or minimal running costs
  • unlikely to work on a large scale but can work on small islands
26
Q

Explain how tidal barrages work?

A
  • they’re big dams built across river estuaries with turbines in them. As the tide comes in it fills up the estuary, and is allowed through the turbines at a controlled speed
  • tides are produced by the gravitational pull of the sun and moon
27
Q

Explain the advantages and disadvantage if tidal barrages?

A
  • there’s no pollution
  • tides are quite reliable they always happen twice a day and near the predicted height. The height of the tide is variable, lower tides provide a lot less energy than big tides. Also doesn’t work if the water level is the same either side of the barrage (this happens 4 times a day)
  • initial costs are modestly high but there’s no fuel or minimal running cost
  • only some estuaries are suitable for tidal power, tidal power has the potential to generate a lot of energy
28
Q

What are bio-fuels?

A
  • renewable energy resources created from plant products or animal dung
  • it can be a solid, liquid or gas and ce be burnt to produce electricity or run cars in the same way as fossil fuels
  • they’re carbon neutral do you grow the plants the rate you’re burning things
29
Q

What are the advantages and disadvantages of bio-fuels?

A
  • bio-fuels are quite reliable, crops don’t take long to grow and different crops can be grown all year round.
  • Can’t respond to immediate energy demands, but can stored for when needed
  • costs to refine bio-fuels are high and there’s a concern the crops specifically for bio-fuels means less water and space to meet the demands for crops that are grown for food
  • large areas have been cleared in some areas to make room for bio-fuels, so species gave lost they habitats. The decay ans burning of vegetation increases CO2 and methane emissions

GCSE PPaper1 (8 decks)

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