11/11/15 Test Flashcards
(129 cards)
1
Q
What are the worst conductors of energy?
A
Gas
2
Q
Give two examples of good insulators
A
Wool and fibreglass
3
Q
Why is wool a good insulator?
A
It traps air between the fibres
4
Q
What makes metals so good at conducting?
A
The free electrons transferring energy inside the metal
5
Q
Why are non metals poor conductors?
A
They have no free electrons. In a non metal solid energy transfer only happens because the atoms vibrate and pass on the vibrating by ‘shaking’ their neighbours. This is much less effective.
6
Q
Why are gases the worst conductors?
A
Their atoms are far apart and so vibrations and passed on very slowly
7
Q
What is a good insulator for a window?
A
Doubt glazing
8
Q
What material is used to insulate a house loft
A
Fibreglass
9
Q
What is the handle of a frying pan made of
A
Plastic or wood
10
Q
A radiator central heating system is made from…
A
Steel
11
Q
What is convection
A
The circulation of a fluid (liquid or gas) caused by heating it.
12
Q
Where does convection take place
A
In liquids and gases
13
Q
What happens when you heat a liquid or gas?
A
It becomes less dense (molecules move faster and further apart) so it rises and causes circulation
14
Q
When a fluid is heated, it _____ and _____ with the rest of the fluid
A
Rises / mixes
15
Q
What is infrared radiation
A
Energy transfer by electromagnetic waves
16
Q
What are the best conductors of energy?
A
Metals
17
Q
Where is a spectrum hottest?
A
Just beyond the red end
18
Q
Give examples of electromagnetic waves
A
Radio waves, microwaves, IR radiation, visible light, ultra violet radiation, x rays, gamma rays
19
Q
The hotter an object is the _____ it emits IR
A
Faster
20
Q
Emit means….
A
Give out
21
Q
All objects give out what?
A
Infrared radiation
22
Q
Why do penguins huddle together to keep warm?
A
With someone next to you, you cannot lose heat through infrared radiation
23
Q
What type of surfaces emit and absorb the most IR?
A
Dark Matt surfaces
24
Q
What type of surfaces reflect IR best?
A
Light, shiny surfaces
25
Why do Matt surfaces absorb and emit infrared better than shiny surfaces?
Matte surfaces are uneven and a have a much larger surface area.
26
Why do Matt surfaces not reflect light?
Their surfaces are uneven, meaning the light is reflected back in all different directions.
27
Why does ice on a road melt faster in sunshine if sand is sprinkled on it?
The sand, which is a matte colour, absorbs the heat and makes the ice hotter, meaning it melts more quicker. (Ice reflects the heat)
28
Energy transfers from our homes can be reduced by fitting
```
Loft insulation
Cavity wall insulation
Double glazing
Draught proofing
Aluminium foil behind radiators
```
29
How do animals keep cool?
They keep cool in different ways, but most of the ways involve a large surface area through which blood is pumped so that heat can be released through the skin and removed by convection. Eg elephants ears
30
Heat energy always goes from ____ to ____
Hot / cold
31
The vacuum between the glass walls of a vacuum flask reduces
Conduction and convection
32
The silvered surface of the glass walls of a vacuum flask reduces
Radiation
33
The stopper in the opening of a vacuum flask reduces
Convection and evaporation
34
Heat is transferred by the air molecules away from the vacuum flask by
Convection
35
Give the method used for reducing heat energy loss in the roof
Glass fibre insulation in the loft
36
Give the method used for reducing heat energy loss in walls
Cavity wall insulation
37
Give the method used for reducing heat energy loss in the floor
Carpets
38
What is evaporation
When a liquid turns into a gas
39
What is condensation
When a gas turns into a liquid
40
Cooling by evaporation of a liquid is due to the....
Faster moving molecules escaping from the surface of a liquid
41
Evaporation can be increased by:
Increasing the surface area of the liquid
Increasing the liquids temperature
By creating a draught (wind) of air across the liquids surface
42
Condensation on a surface can be increased by
Increasing the are of the surface or reducing the temperature of the surface
43
Why does opening a window in a steamy room clear the condensation
The wind coming through the window increases evaporation speed. When the molecules escape into the surrounding air it evaporates. Also, it cools the room down
44
Why does washing in a line take longer to dry on a damp day?
The air itself is wet; there's nowhere for the moisture to go.
45
Why do the windows on a bus become misty when there are lots of people on the bus.
The warm, moist breath from the people will condense on the cold windows.
46
A person wearing wet clothes on a cold windy day is likely to feel much colder than someone wearing dry clothes. Why?
The most energetic molecules will leave, leaving the person with less heat energy and making them colder
47
The rate of energy transfer to or from an object depends on
The shape, side and type of material of the object
The materials the object is in contact with
The temperature difference between an object and it's surroundings
48
Kinetic energy:
Energy possessed by and object by virtue of its speed and mass
49
GPE
Energy possessed by an object by virtue of its position in the gravitational field (height above the earth)
50
Chemical potential energy:
This energy is stored in the chemical bonds of substances such as fuels eg petrol, rocket fuel
51
Light:
Sunlight reaching the earth transfers large amounts of energy eg it makes plants grow, heats water and can be turned into electricity
52
Elastic:
This is the energy contained in stretched objects. When they return to their natural shape they can do work eg bow and arrow
53
Electrical:
Electrical charges (electrons) moving through a piece of wire can do work, eg turned into heat and light in a light bulb
54
Nuclear:
This energy is stored in the nuclei of all atoms. This energy is released during a nuclear reaction eg a reactor in a nuclear power plant
55
Sound
Sound waves can carry energy which can e transferred eg into electrical signals in the ear or in a microphone
56
Thermal:
Particles which are at a high temperature have more energy than those at a low temperature. Thy van transfer this energy and do work in the process.
57
Energy cannot be ____ or ____
Created / destroyed
58
Assuming there is no friction, the total amount of energy always....
Remains the same
59
Energy is measured in
Joules
60
What is useful energy
Energy in the place we want it and in the form we need it
61
What is wasted energy
Energy that is not useful
62
Where are both useful and wasted energy transferred to
The surroundings, which become warmer
63
What does dissipated mean
As energy spreads out, it gets more and more difficult to use for further energy transfers.
64
What does air resistance cause energy to do
Be lost as heat
65
The efficiency of a device:
Useful energy transferred by the device/total sent y supplied to the device x 100%
66
How do make machines more efficient:
Reduce friction, air resistance, electrical resistance and noise due to vibration
67
The useful energy from a machine is always less than the total energy _________ it
Supplied to
68
friction between the moving parts of a machine causes energy to be ________ the machine
Wasted by
69
Work done means...
Energy used/transferred
70
Work done =
Force x distance
71
Marcia pushes a shopping trolley full of chocolate, the further she pushed it the more ...
Work she has to do and the more energy she uses
72
The heavier something is the _____ work has to be done to push it the same distance
More
73
The amount of work done depends on:
The size of the force used
| The distance moved
74
Gravitational potential energy = (calculation)
Weight of object x height lifted (m x g x h)
G = 10
75
The kinetic energy of an object depends on :
The mass of the object
It's speed (or velocity)
76
Kinetic energy = (calculation)
1/2 x m x v squared
77
What is energy
The ability to do work
78
What does the amount of work done indicate
How much energy has been transferred from one form to another
79
Power is...
The rate of working (the rate of transferring energy)
80
Power = (calculation)
Work done/time taken
81
What does not happen in convection?
Particles do not themselves expand
82
What happens in evaporation?
High energy particles leave the surface, reducing the temperature of the remaining liquid
83
What is a non renewable energy resource
One that effectively cannot be replaced once it has been used
84
What are electricity generators in power stations driven by?
Turbines
85
Where do coal, oil and natural gas burn?
In fossil fuel power stations
86
What are used as fuel in nuclear power stations?
Uranium or plutonium
87
Uranium or plutonium releases ____ _____ energy that fossil fuels
Much more
88
_______ are renewable sources of energy
Biofuels
89
Give two examples of biofuels
Methane and ethanol
90
What can biofuels be used for
Generating electricity
91
What do fossil fuels give off?
Greenhouse gases
92
In coal fired power stations , giving the energy transfer
Fuel ---> heats up water into steam ---> steam drives turbine ---> turbine turns generator ---> electricity
Chemical --> thermal --> kinetic --> electrical
93
Feedstock biomass comes from...
Grasses, wood and lawn waste
94
How do we get ethanol from biomass
Feedstock biomass comes from grasses, wood and lawn waste
Enzymes break down the plant cellulose fiber into glucose and other sugars
Ethanol fuel is created by fermenting sugars
Fuel grade ethanol is separated from the solution by distillation
H2O is recycled from distillation, and separated plant lignin is burned for energy to run the facility
95
What kind of waste to nuclear power station diagrams have
Radioactive waste
96
Give an example of carbon neutral
Trees absorb carbon whilst alive and give off the same amount when burnt for fuel.
97
The fuel that is not a fossil fuel is
Uranium
98
Power stations that use ____ as the fuel can be switched on very quickly
Gas
99
Green house gases are produced in a power station that uses coal, _____ or _____ as fuel
Gas, oil
100
Give an advantage and a disadvantage of an oil fired power station compared with a nuclear power station
No radioactive waste
| Gives off greenhouse gases
101
Give an advantage and a disadvantage of a gas fired power station compared with a coal fired power station
They can be switched on very quickly
| Gas supplied might run out more quickly
102
What is a wind turbine
An electricity generator on top of a tall tower
103
How do waves generate electricity
By turning a floating generator
104
How are hydroelectricity generators turned
By water running downhill
105
What does a tidal power station do
It traps each high tide and uses it to turn generators
106
____ power does not need water
Wind
107
____ power does not need energy from the sun
Wave
108
______ power is obtained from water running downhill
Hydroelectric
109
_____ power is obtained from water moving up and down
Tidal
110
What does wind power transfer
Kinetic energy (wind) --> kinetic energy (turbine) --> electrical energy (generator)
111
What does tidal power transfer
Kinetic (water) --> kinetic (turbine) --> electrical (generator)
112
How does the tidal electricity generation work?
It works as the tide comes in and again when it goes out. The turbines are driven by the power of the sea in both directions.
113
Hydro electric power station transfers
GPE (height) --> kinetic (water) --> electrical (generator)
114
Wave power transfers
Kinetic (wave) --> electrical energy (generator)
115
What are solar cells
Flat solid cells that convert solar energy directly into electricity
116
What are solar heating panels
Panels that use the suns energy to heat water directly
117
What does geothermal energy come from
The energy released by radioactive substances deep inside the earth
118
What does water pumped into hot rocks underground produce?
Steam to drive turbines that generate electricity
119
Solar cells transfer
Light energy to electrical energy
120
Solar panels use...
Infrared radiation from the sun to heat up water
121
Geothermal power transfers
Heat energy to kinetic energy to electrical energy
122
Renewable energy resources can affect
Plant and animal life
123
Acid rain =
Sulfur dioxide (SO2) from coal
124
Carbon capture and storage =
Reduces greenhouse emissions from power stations
125
Why is nuclear fuel non renewable
It cannot be reused/grown/made
126
List three renewable energy sources that could be used to generate electricity for people on a remote flat island in a hot climate
Hydroelectricity
Solar
Wind
127
List three types of power stations that do not release greenhouse gases into the atmosphere
Nuclear
Geothermal
Hydroelectric
128
The sulphur in coal can cause...
Acid rain
129
Fossil fuels are ______
Reliable
