unit 2 - energy, materials, systems and devices

Question 1

energy generation

Answer 1

the process of creating electricity from other forms of energy,
such as water, wind, nuclear fusion, fossil fuels, and solar power.

Question 2

nuclear power

Answer 2

nuclear fuels release energy
through nuclear reactions, rather
than through chemical reactions

Question 3

elastic energy source

Answer 3

energy stored in an object due to a
force that temporarily changes its shape, such as squashing or stretching.

Question 4

biofuel energy source

Answer 4

• energy stored in an object due to a force that temporarily changes it shapes e.g squashing

Question 5

thermal energy source

Answer 5

• heats water ,steam turns turbine and start electrical generator

Question 6

turbine and generator

Answer 6

• fossil fuels burnt to generate electricity
• energy transferred by heating causes water to boil
• steam rises and turns turbine
• turns on generator
• energy generated goes to national grid through pylons ( homes, schools, shops etc)

Question 7

fracking or hydraulic fracturing

Answer 7

• used to extract natural gas from shale rock (contain gas in small spaces)
• drill deep holes in shale
• pump mixture of water, sand and chemicals into holes at high pressure
• open up fractures in the rock
• allow trapped gas to flow into collection wells
• pipe gas away for commercial use

Question 8

why is fracking controversial?

Answer 8

• can cause earthquakes
• requires a lot of water
• releases greenhouse gases

Question 9

nuclear power

Answer 9

• nuclear energy from nuclear reaction that takes place inside a reactor vessel
• nuclear energy converted to heat energy
• heat used to change water into steam in a boiler
• steam drives turbine
• drives generator to produce electricity

Question 10

nuclear power advantages

Answer 10

• do not produce carbon dioxide or
  sulphur dioxide
• reliable sources of energy, can meet increases in demand
• 1kg = millions times more energy than 1kg of coal

Question 11

why is nuclear power controversial?

Answer 11

• non-renewable
• accidents = large amounts of radioactive material released into environment
  -nuclear waste is hazardous

Question 12

Fukushima Daiichi

Answer 12

• nuclear disaster in Japan
• march 11
• tsunami and earthquake caused outage at plant

Question 13

Chernobyl

Answer 13

• nuclear power plant accident
• ukraine in 1986
• released massive amounts of radiation into environments
• reactor design flaws and unsafe procedures = power surge, steam explosion and fire

Question 14

composite materials

Answer 14

two or more materials with different properties combined to produce a material with improved properties

Question 15

composite materials have 2 components…

Answer 15

• the reinforcement
• the matrix (binds reinforcement together)

Question 16

reinforced concrete

Answer 16

• steel - tensile strength > compressive strength
• concrete - compressive strength > tensile strength
• strong and slightly flexible, important when constructing large buildings and structures

Question 17

fibreglass

Answer 17

• glass fibres - low density, strong in tension (not easily stretched but flexible)
• polymer resin - not strong but stiff
• composite = strong, stiff, lightweight

Question 18

carbon fibre reinforced polymer

Answer 18

• carbon fibres
• polymer resin
• same as fibreglass

Question 19

chipboard

Answer 19

• wood chips - reinforcement of cellulose fibres bonded by lignin, fibres in one direction = wood stronger in one direction
• resin glue
• strong in all directions