SP3 Conservation of Energy Flashcards
1
Q
What are the different ways energy is stored in?
A
- chemical
- kinetic
- thermal
- elastic potential
- gravitational potential
- nuclear
- magnetic
- electrostatic
2
Q
Define chemical energy
A
Energy between bonds
3
Q
Define kinetic energy
A
Energy stored in moving objects
4
Q
Define thermal energy
A
Energy stored in hot objects
5
Q
Define elastic potential energy
A
Stored in stretched, squashed or twisted materials
6
Q
Define gravitational potential energy
A
Energy stored in high positions of objects within a gravitational field
7
Q
Define nuclear energy
A
Energy stored within atoms
8
Q
Define magnetic energy
A
Energy stored within a magnetic field
9
Q
Define electrostatic energy
A
Energy between two charges
10
Q
State the law of conservation of energy
A
Energy cannot be created or destroyed, only stored and transferred. This means that all energy in a system has to go somewhere, it can’t be lost
11
Q
What are the units for energy?
A
J (Joules)
12
Q
Give an example of magnetic energy
A
- magnets
- compasses
13
Q
Give an example of thermal energy
A
- human bodies
- hot coffees
- stoves
14
Q
Give an example of chemical energy
A
- food
- muscle cells
- electrical cells
15
Q
Give an example of kinetic energy
A
- runners
- buses
- comets
16
Q
Give an example of nuclear energy
A
- uranium nuclear power
- nuclear reactor
17
Q
Give an example of electrostatic energy
A
Thunderclouds
18
Q
Give an example of elastic potential energy
A
- springs
- inflated balloons
19
Q
Give an example of gravitational potential energy
A
- planes
- kites
- mugs on a table
20
Q
What are Sankey diagrams?
A
- Used to show the amount of energy transferred
- width of the arrow represents the amount of energy in joules
21
Q
How can energy be transferred?
A
- mechanical work
- electrical work
- heating
- radiation
22
Q
Define mechanical work
A
A force moving an object through distance
23
Q
Define electrical work
A
Charges moving due to a potential difference
24
Q
Define heating as a method of energy transfer
A
Due to temperature difference caused electrically or by chemical reaction
25
Define radiation as a method of energy transfer
Energy transferred as a wave
26
What are the two different types of radiation?
- conduction
- convection
27
Why does conduction occur?
Vibration of particles due to heating. This vibration moves along the material, thereby moving the heat energy
28
In what materials does conduction take place?
Solids: mainly in metals
29
When does convection occur?
When part of a fluid is warmer than the rest and rises
30
Describe a convection current
Warm air rises and cold air sinks, so warm air is at the top and cold air is at the bottom
31
In what materials does convection occur?
Liquids and Gases
32
What is a conductor?
A material in which heat and electricity can pass through easily
33
What is an insulator?
A material in which heat and electricity cannot pass through easily
34
Define thermal conductivity
A measure of how quickly energy can be transferred via conduction through a metal
35
What is the rate of energy transfer reduced by?
- increasing thickness
- decreasing thermal conductivity
- decreasing temperature difference
36
What is efficiency?
A way of describing how good a machine is at transferring useful energy, in comparison to its input
37
What is the formula for efficiency?
useful energy/total energy
38
How can mechanical devices be made more efficient?
Lubricant to reduce friction between its moving parts
39
What is the formula for gravitational potential energy?
m x g x change in h
40
What is the formula for kinetic energy?
1/2 x m x v^2
41
Define non-renewable resource
Resources that are not replenished; they will run out someday
42
Give some examples of non-renewable resources
- coal
- oil
- natural gas
- nuclear fuels
43
What are the advantages of coal?
- can be used for old-fashioned trains
- burnt in fireplaces and barbecues
44
What are the advantages of oil?
- petrol and diesel are fossil fuels made from oil
- store a lot of energy
- easy to store and use in energies
45
What are the advantages of natural gas?
- causes less pollution than burning coal
- emits less CO2 than other fossil fuel powered stations while producing the same amount of energy
46
What are the advantages of nuclear fuel?
- stores a lot of energy in small amounts
- useful for spacecraft where the mass of the fuel is important
- reliable as it meets current demand
- relatively cheap
- clean: doesn't release any greenhouse gases/ harmful chemicals into the atmosphere
47
What are the disadvantages of coal?
- carbon dioxide is produced
- expensive
- contributes to climate change
48
What are the disadvantages of oil?
- harmful energy produced that contributes to global warming
- will run out one day
- releases sulfur impurities which causes acid rain
49
What are the disadvantages of natural gas?
- harmful gases produced
50
What are the disadvantages of nuclear fuel?
- highly radioactive waste produced which is difficult to get rid off
- overall cost of nuclear fuel is high
51
Define renewable resource
A resource that will be replenished; it will never run out
52
Give some examples of renewable resources
- geothermal
- water waves
- solar cells
- hydroelectricity
- wind
- tidal
- biofuels
53
What are some advantages of solar energy?
- can convert solar energy directly into electrical energy
- can be used anywhere
- no pollution
- free energy
- low running costs
- doesn't produce co2
54
What are some advantages of hydroelectricity?
- available at any time as long as reservoirs don't dry up
- can be started and stopped quickly unlike fossil fuel power stations
- can produce large amounts of energy and provide an immediate response for demand
55
What are some advantages of wind turbines?
- produces no co2
- efficient as it produces electricity 70-85% of the time
56
What are some advantages of tidal power?
- no fuel costs and minimal running costs
- reliable: happens twice a day without fault
- significant amount of energy generated
57
What are some advantages of geothermal power?
- heats buildings directly without the need to generate electricity
- reliable free energy
58
What are some advantages of biofuels?
- overall process is carbon neutral
- fairly reliable: short time to grow crops + crops can grow all year round
- can be made from waste food
59
What are some advantages of wave power?
- fairly useful to generate electricity on a small scale
- no fuel costs
- minimal running costs
60
What are some disadvantages of wave power?
- many required to produce sufficient energy: spoils the view
- unreliable: depends on wave motion
- initial costs high
- structures can disturb habitats and are hazardous to boats
61
What are some disadvantages of biofuels?
- extra energy is needed to grow the crops or feed the animals
- competition for space and water with crops that are grown for food
62
What are some disadvantages of geothermal energy?
- difficult to find suitable location
- cost of building is high
63
What are some disadvantages of tidal power?
- structure spoils view
- not many places suitable for barrages
- disturbs habitats
- prevents free access by boats
- high initial manufacturing costs
64
What are some disadvantages of wind turbines?
- can be noisy
- large number needed to produce sufficient energy
- ruins scenery
65
What are some disadvantages of hydroelectricity?
- a possibility of flooding the valley, leading to rotting vegetation
- needs a constant supply of falling water
- loss of habitats
- inconvenient: some villages evacuated to build
66
What are some disadvantages of solar energy?
- not available all the time
- initial costs high
- solar power only works when the sun is out in the daytime
- can require a lot of space
- only powers some homes
67
How can efficiency be increased?
- reducing waste output
- recycling waste output
68
How is heat loss prevented in buildings?
- thicker walls mean greater thermal insulation: less heat loss
- air cavities between walls causes lots of heat loss through convection, which is solved through a cavity wall
69
How can we reduce wasted energy?
- lubricate systems: less friction and heat created
- thermal insulation: less heat lost
