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Intergrated science > Energy > Flashcards

Energy Flashcards

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Biology 101 flashcards
1
Q

use of energy of living things

A

to stay alive and carry out their daily activities

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2
Q

use of energy of animals and plants

A

to grow

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3
Q

use of energy of humans

A

to power our appliances and machines

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4
Q

Forms of energy

A
  • Sound energy
  • chemical energy
  • light energy
  • thermal energy
  • kinetic energy
  • potential energy
  • electrical energy
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5
Q

sound wave

A

a form of mechanical energy

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6
Q

how does sound travel

A

it travels through gas, liquids, solids as sound waves

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7
Q

when is sound energy given out

A

when an object vibrates

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8
Q

chemical energy

A

energy stored in the bounds of chemical compounds

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9
Q

examples of things that store chemical energy

A
  • food
  • fuels (such as wood, charcoal and petrol)
  • batteries
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10
Q

use of chemical energy stored in food for humans

A

to help us stay alive, grow and carry out our activities

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11
Q

when fuels are burned, the chemical energy stored in them is _____

A

released as other forms of energy

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12
Q

use of chemical energy stored in batteries

A

provide energy for small electrical appliances and other devices

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13
Q

Light enables us to ____

A

see things

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14
Q

Use of light for plants

A

to make food

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15
Q

an object with ______ has more thermal energy

A

higher temperature

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16
Q

all moving objects have _____

A

kinetic energy

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17
Q

what is the amount of kinetic energy of an object related to

A

its speed and mass

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18
Q

the faster an object moves, the more ______ it has

A

kinetic energy

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19
Q

the greater the _____ of an object, the more kinetic energy it has

A

mass

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20
Q

when does an object gain potential energy

A

when it is raised to a higher position

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21
Q

the higher the position of the object, the more _____ it has

A

potential energy

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22
Q

some objects also store potential energy when they are _____ or _____

A

stretched or compressed

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23
Q

example of object that gain potential energy when it is stretched

A

bow

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24
Q

example of object that gain potential energy when it is compressed

A

pilers

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25
Q

electrical energy is the most widely used ___________

A

energy form at home

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26
Q

______ need electrical energy to work

A

all electrical appliances

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27
Q

how is electrical energy supplied

A
  • supplied from power stations, transmitted to our homes through power cables
  • obtained from batteries
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28
Q

what are some things in nature that carry electrical energy

A

lightning, electric eels

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29
Q

units of energy

A
  • joule
  • kilojoule
  • calorie
  • kilocalorie
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30
Q

one cal = ?

A

4.18 J

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31
Q

where is the unit cal commonly used

A

for measuring the energy value of food

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32
Q

the process of energy converting into different forms

A

energy conversion

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33
Q

law of conservation of energy

A

energy can be converted from one form into another but cannot be created or destroyed

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34
Q

use of sankey diagram

A

to show an energy conversion process

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35
Q

Energy converters

A

devices or appliances we use to convert energy from one form into another form of useful energy in daily life

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36
Q

example of an energy converter and how it works

A

the lamp converts electrical energy into light energy and thermal energy. Light energy is the useful energy which enables us to see things in the dark.

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37
Q

efficiency of an energy converter = ?

A

Useful energy output / total energy output * 100%

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38
Q

in the sankey diagram, the useful energy output goes ___ and the non-useful energy output goes _____

A

straight, sideways

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39
Q

heat

A

energy transeferred from a hotter object to a colder one

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40
Q

processes of heat transfer

A
  • conduction
  • convection
  • radiation
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41
Q

conduction requires a _______ such as a solid, a liquid or a gas to transfer ____

A

medium, heat

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42
Q

heat always flows from _____ to ______

A

hot, cold

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43
Q

conduction can take place in an object, or two objects _______

A

in contact

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44
Q

good conductors of heat

A

metals (such as copper and iron)

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45
Q

poor conductors of heat are also called

A

insulators of heat

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46
Q

poor conductors of heat

A

non-metal (such as plastic and wood)

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47
Q

water and liquids are ____ conductors of heat

A

poor

48
Q

uses of good conductors of heat

A
  • cooking utensils
  • heat sink
49
Q

uses of poor conductors of heat

A
  • handles of cooking utensils
  • down clothing
50
Q

why can down jackets keep us warm

A

fur and feathers can trap a lot of air inside them. Since air is a poor conductor of heat, we can wear down jackets to keep warm

51
Q

convection current of air/water

A

hot air/water rises, cold air/water sinks

52
Q

process of convection

A

the convection current carries heat from one place to another

53
Q

what medium can convection take place in

A

liquids and gases

54
Q

definition of convection

A

the transfer of heat from one place to another by the movement of a liquid/gas

55
Q

electrical appliances that use convection

A
  • electric kettle
  • air conditioner
56
Q

effects of convection currents in nature

A

sea breezes and land breezes

57
Q

the space between the sun and the earth is a ___

A

vacuum

58
Q

heat is transferred from the sun to the earth by ______

A

radiation

59
Q

hear can be transferred through a vacuum by ______

A

radiation

60
Q

________ absorb radiation

A

all objects

61
Q

the temperature of an object ____ when it absorbs radiation

A

increases

62
Q

dull black surfaces are good ________
while shiny silver surfaces are poor _____________

A

absorbers and emitters of radiation, absorbers and emitters of radiation

63
Q

Light-coloured objects absorb ____ radiation than dark-coloured objects

A

less

64
Q

____ emit radiation

A

all objects

65
Q

applications of radiation in real life

A
  • heat radiator
  • cooking utensils
66
Q

fossil fuels are our main ______

A

energy sources

67
Q

examples of fossil fuels

A
  • coal
  • crude oil
  • natural gas
68
Q

fossil fuels that are used directly as fuel

A

coal and natural gas

69
Q

where is coal mainly used

A

in power stations to generate electricity

70
Q

the burning of coal supplies

A

40% of the world’s electricity

71
Q

crude oil is ______ to produce several types of fuels

A

processed

72
Q

types of fuels produced by crude oil

A
  • pretrol
  • LPG
  • diesel oil
73
Q

use of natural gas in some countries and Hong Kong

A

some countries: for cooking and as fuels in cars
hong kong: for generating electricity and to produce town gas

74
Q

fossil fuels take a very long time to _______ after they are used. They are called ________ energy sources

A

replenish, non-renewable

75
Q

fossil fuels’ reserves are ______

A

limited

76
Q

problems of burning fossil fuels

A
  • releases many harmful substances such as lead
  • produces a large amount of carbon dioxide
77
Q

when the harmful substances are released into the air, they cause _______

A

air pollution

78
Q

health problems caused by air pollution

A
  • irritate our eyes and throat
  • cause dizziness and headaches

breathing in harmful substances for a long time: respiratory diseases such as ashma

79
Q

______ and _______ can trap heat in the atmosphere

A

carbon dioxide, nitrogen oxides

80
Q

trap heat gases increase
–> average temperature _______
–> __________
–> rise in ______
–> low-lying ______ may face a high risk of _______

A

increases, global warming, sea level, coastal areas, flooding

81
Q

_______ and _____ can dissolve in rainwater to form ________

A

sulphur dioxide, nitrogen oxides, acid rain

82
Q

harms of acid rain

A
  • harm to fish and other aquatic life
  • damages trees, plants and buildings made of metals or stone
83
Q

the burning of fossil fuels cause harm to __________

A

our health and our environment

84
Q

nuclear fuel

A

uranium

85
Q

is nuclear power a renewable energy source

A

no

86
Q

Why is nuclear power a non-renewable energy source

A

because nuclear fuel (uranium) is non-renewable

87
Q

about 25% of electricity used in Hong Kong comes from the __________________

A

Guangdong Daya Bay Nuclear Power Station in Dapeng, Shenzhen

88
Q

the process in nuclear power station to produce electricity

A

nuclear fuels undergo reactions which release heat. The heat is used to boil water to steam. The steam drives a turbine, which in turn drives a generator that produces electricity

89
Q

a small amount of nuclear fuel can generate a ________

A

large amount of electricity

90
Q

limitations of nuclear power

A
  • the nuclear fuel supply is limited
  • nuclear fuels and the waste produced in nuclear power stations are highly dangerous. They are harmful to our health and cause pollution to the environment. Therefore, they need to be stored and transported properly.
91
Q

types of renewable energy

A
  • solar energy
  • wind power
  • hydroelectric power
  • biomass energy
92
Q

solar energy is supplied by ______

A

the sun

93
Q

_________ are commonly installed on the roofs of buildings to collect solar energy

A

solar panels

94
Q

use of solar energy

A

to produce hot water or generate electricity

95
Q

limitations of solar energy

A
  • the energy supply is affected by day length and sunlight intensity
  • special equipment is needed to collect sunlight. This equipment is costly to build and install
96
Q

use of wind power
(then & now)

A

then: for grinding grains and to move boats and ships
now: converted into electrical energy using wind turbines

97
Q

wind

A

the kinetic energy of air

98
Q

process of generating wind power

A

when the wind blows, the turbine rotated and drives a generator which produces electricity

99
Q

limitations of wind power

A
  • the supply of wind power depends on the availability and speed of wind
  • wind turbines also cause noise pollution and birds are sometimes killed by the blades of wind turbines
  • wind turbines make the landscape look unsightly
100
Q

process in a hydroelectric power station

A

the water in the reservoir is at a higher position. when the gates in the dam open, the water in the reservoir will flow down. potential energy of the water is then converted into kinetic energy. the flowing water drives a turbine, which in turn drives a generator to produce electricity

101
Q

limitations of hydroelectric power

A

the constuction of large dams destroys local land and water habitats. This causes harm to the animals and plants living there. people living near a dam site may also need to move to other places

102
Q

when wood, crops and animal waste are burned, the chemical energy stored in them is converted into _____________

A

heat and light energy

103
Q

the chemical energy stored in plants or in animal waste

A

biomass energy

104
Q

why is biomass energy a renewable energy source

A

because its supplies can be replenished in a short period of time

105
Q

use of biomass energy
(then & now)

A

then: for heating and cooking
now: to extract sugar, starch or oil, produce biofuels with food waste

106
Q

use of biofuels

A

to power vehicles, for heating or cooking

107
Q

limitations of biomass energy

A
  • a large area of land is needed to grow crops used for the production of biofuels. The use of agricultural plants as biofuels may increase the prices of crops
  • if unused waste is not treated properly, it may release gases with a foul smell and attract pests such as rats and flies
108
Q

actions to save energy in daily life

A
  • turn off electrical appliances when they are not in use
  • choose electrical appliances with grade 1 energy efficiency labels.
  • set the air conditioner to keep a moderate temerpature
  • hang clothes to dry instead of using a dryer
  • use public transport instead of private vehicles
  • use the staircase instead of taking a lift if only a short distance
109
Q

advantages of grade 1 energy efficiency electrical appliances

A

they use less energy than the same type of appliance with other ratings

110
Q

new technologies to save energy

A
  • energy-saving escalator
  • double glazing windows
  • light tubes
  • electric vehicles
111
Q

energy-saving escalator

A

it runs at normal speed when people walk near to it, but runs at a slower speed when it is not in use

112
Q

double glazing windows

A

it traps a layer of air between two panels of glass. as air is a good insulator of heat, the windows keep the room cool by blocking out the heat from the sun

113
Q

advantages of double glazing windows

A

it helps reduce the electricity used by air conditioners

114
Q

light tubes

A

they can capture sunlight and reflect it into the building

115
Q

advantages of light tubes

A

they cut down the energy needed for lighting

116
Q

advantages of electric vehicles

A

they use less energy than petrol cars

117
Q

we can reduce the use of fossil fuels by saving energy and developing ______________

A

energy-saving technologies

Intergrated science (4 decks)

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