Energy Resources and Transfer

Question 0

What’s potential/chemical energy

Answer 0

Gravitational potential, elastic potential, chemical energy are forms of stored energy because the energy isn’t doing anything, only waits to be turned into another form.

Question 1

Conservation of energy:

Answer 1

Energy can never be created or destroyed, only transferred from one form to another.

Question 2

Examples of electrical, nuclear, gravitational potential energy:

Answer 2

Electrical: whenever a current flows

Nuclear: released only from nuclear reactions

Gravitational potential energy: possessed by anything which can fall

Question 3

Energy always ends up as…

Answer 3

Heat/thermal energy.

Question 4

Archer/bow energy transfers:

Answer 4

Chemical ➡️ elastic potential (pulling back)

(Letting go) elastic potential ➡️ kinetic

(Heat and sound also)

Question 5

How does conduction happen?

Answer 5

Conduction of heat is the process where vibrating particles pass on their extra kinetic energy to neighbouring particles. (Mainly in solids)

Question 6

How does radiation happen?

Answer 6

Transfer of heat by electromagnetic waves. Emission of thermal radiation occurs in solids, liquids, gases. Bigger the temp difference, faster heat is transferred between body and surroundings.

Doesn’t rely on particles- can happen in vacuums

Question 7

How does convection happen?

Answer 7

Convection occurs when the more energetic particles move from the hotter region to the cooler region - and take their heat energy with them.

Question 8

Explain convection currents in every day phenomena

Answer 8

Immersion heater - heat energy transferred from heater coils to water by conduction (particle collision)

Particles near coils get more energy, move faster so there’s more distance between them- the water expands and becomes less dense.

Hotter less dense water tends to rise above the cooler dense water. And moves the cooler water away to sink towards the heater cools.

Cold water heated by coils, rises. Convection currents, circulating heat energy through the water.

Same with air with a radiator!

(They’re all about changes in density)

Question 9

Where is convection most efficient?

Answer 9

In roundish, squarish containers because they allow the convection currents to work best.

No - shallow, wide/ tall,thin containers

Question 10

How do humans reduce heat transfer

Answer 10

In cold, hair on skin stands up to trap a thicker layer of insulating air around body. Limits heat loss by convection, conduction as airs an insulator (particles are spread out)

Clothes - pockets of air trapped between layers reduce by convection, conduction, radiation - material absorbs some heat radiated out by our bodies.

Question 11

Loft insulation stops heat loss in the home:

Answer 11

Thick layer of fibreglass wool on loft floor - conduction (airs an insulator) convection (convection currents can’t be made- fibres trap air- no space), radiation (absorbs heat)

Question 12

Cavity wall insulation stops heat loss in the home:

Answer 12

Foam squirted into gap between bricks - conduction (airs an insulator- air pockets in foam trap air) convection (convection currents can’t be made), radiation (absorbs heat)

Question 13

Draught-proofing stops heat loss in the home:

Answer 13

Strips of foam and plastic around doors and windows stop draughts of cold air being blown in. (Convection)

Question 14

Hot water tank jacket stops heat loss in the home:

Answer 14

Lagging such as fibre glass wool -conduction, radiation

Question 15

Double gazing stops heat loss in the home:

Answer 15

Two layers of glass with a narrow air gap between - reduce conduction (airs an insulator) convection (gap too small to allow air to circulate)

Question 16

Thick curtains stops heat loss in the home:

Answer 16

Big bits of cloth over the window to reduce heat loss by conduction (insulator) and radiation (absorb the heat)

Question 17

When a force moves on an object…

Answer 17

Energy is transferred and work is done

Work done is equal to energy transferred (both joules)

When you do work against friction, most of energy is transformed into heat, some into sound. Generally “wasted” energy

Question 18

understand how conservation of energy produces a link between gravitational potential energy, kinetic energy and work:

Answer 18

When falling, gpe is converted into KE.

KE gained = GPE lost

work is being done while energy is being transferred
(KE ➡️ GPE, GPE ➡️ KE)

Question 19

What’s power?

Answer 19

The rate of transfer of energy/rate of doing work

Question 20

Advantages of fossil fuels (coal, oil, gas):

Answer 20

• release a lot of energy, relatively cheaply
• doesn’t rely on weather- reliable
• lots of fossil fuel power stations already, don’t need to spend on new technology to use them

Question 21

Disadvantages of fossil fuels (coal, oil, gas):

Answer 21

• releases CO2 into the atmosphere when burned in power stations - contributes to global warming
• releases SO2 which causes acid rain. Harms trees, soils, huge impact on wild life
• non renewable - eventually gonna run out

Question 22

Non renewable resources:

Answer 22

Fossil fuels (coal, oil, gas), nuclear fuels (uranium, plutonium)

Question 23

Disadvantages of nuclear fuels:

Answer 23

• Nuclear reactors are expensive to build and maintain, take longer to start up that fossil fuel ones
• processing uranium before using it causes pollution.
• Risks of leaks of radioactive material
• when old and efficient, need to be decommissioned (shut down and made safe) which is expensive

Question 24

Advantages of nuclear fuels:

Answer 24

• no green house gases - global warmi

* plenty of uranium left in the ground (although lot of money and energy to make it suitable for use in a reactor)

Question 25

Advantages of wind energy:

Answer 25

• cheap to run, wind is free
• no polluting waste
• renewable

Question 26

Disadvantages of wind energy:

Answer 26

• visual eyesore - need a lot of them
• very noisy - annoying for people who live near by
• sometimes wind isn’t strong enough to generate power, impossible to increase supply when there’s extra demand. Not reliable
• expensive to set up a wind farm

Question 27

Geothermal energy advantages:

Answer 27

• free, renewable

* no environmental problems

Question 28

Geothermal energy disadvantages:

Answer 28

• drilling down several km is expensive
• cost of building power plant is high compared to amount of energy we can get out of it
• very few places where this seems to be an economic option

Question 29

Solar energy advantages:

Answer 29

• renewable
• expensive initially but energy is free and running costs are almost nothing
• no pollution (although use energy to be manufactured)

Question 30

Solar energy disadvantages:

Answer 30

• very expensive initially
• often not practical/ too expensive to connect to national grid
• not reliable - only if there’s sun. problem at night and in winter in some places.

Question 31

Solar heating systems:

Answer 31

black water pipes in a glass box. glass let’s heat and light from the sun in, which is absorbed by the black pipes and heats the water.

(Cost money to set up but renewable and free after - small scale energy production)

For cooking - curved mirror in a solar oven that focuses the Sun’s light and heat. Provide a renewable energy resource for outdoor cooking. SLOW, BULKY, UNRELIABLE - strong sunlight needed

Question 32

Wave power advantages:

Answer 32

• no pollution
• renewable
• no fuel costs, minimal running costs (but initial costs)

Question 33

Wave power disadvantages:

Answer 33

• unreliable - waves tend to die out when wind drops

• visual eyesore- spoil the view
• hazard to boats
• initial costs are v high
• unlikely to provide energy on a large scale- v useful on small islands

Question 34

Tidal barrages when the tide goes in and out:

Answer 34

Tidal barrages - big dams built across river estuaries with turbines in them. ride comes in-fills up to the height of several metres. water let out through turbines at controlled speed.

Kinetic of water-kinetic of turbine, generator -electrical

Question 35

Tidal barrages good and bad:

Answer 35

• no pollution, renewable, reliable (height of tide is variable -higher, more energy), no fuel costs, minimal running costs
• prevent free access by boats, soil view, altering habitat of wildlikfe
• high initial costs

Question 36

Hydroelectricity:

Answer 36

Catching rainwater. Requires the flooding of a valley by building a dam. Rainwater caught and allowed out through turbines. GPE of water - KE of water - KE turbine - KE generator - Electrical

Question 37

Hydroelectricity good and bad:

Answer 37

• renewable, no pollution, IMMEDIATE RESPONSE TO INCREASED DEMAND, no fuel/low running costs
• big impact of environment - flooding valley (rotting vegetation releases methane and co2), loss of habitat, reservoirs look unsightly when dry up (above all can be avoided by remote valleys)
• problems with reliability in drought
• high initial costs