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Year 7 Science 23/24 > Energy > Flashcards

Energy Flashcards

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1
Q

List the 8 energy stores

A

Chemical, kinetic, gravitational potential, elastic potential, thermal, nuclear, electrostatic, magnetic

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2
Q

List the 4 energy pathways

A

Electrical, mechanical, heating, radiation

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3
Q

Is an object is stationary and then starts moving, which energy store has increased?

A

Kinetic

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4
Q

If I raise an object into the air, which energy store has increased?

A

Gravitational potential

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5
Q

What is the unit of power?

A

watt, W

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6
Q

How do you calculate power?

A

power = energy/time

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7
Q

How many watts in a kilowatt?

A

1000

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8
Q

In fuel bills, energy is given in kWh - what is this unit?

A

kilowatt hours

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9
Q

Name 3 non-renewable energy resources

A

Coal, oil, gas, nuclear

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10
Q

Name 3 renewable energy resources

A

Wind, hydroelectric, solar, wave, geothermal, tidal, biomass

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11
Q

Name 3 fossil fuels

A

Coal, oil, gas

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12
Q

How were fossil fuels formed?

A

Formed from the remains of plants and animals: coal was formed from dead trees and plants; while oil and gas were formed from the remains of marine life that died millions of years ago. As they were buried deeper and deeper enormous pressure and heat turned them into coal/oil/gas

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13
Q

What is released when fossil fuels are burnt

A

carbon dioxide (and other greenhouse gases)

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14
Q

Increasing the number of fossil fuels in the atmosphere increases what effect?

A

The greenhouse effect

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15
Q

What fuel is typically used in nuclear power stations?

A

uranium

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16
Q

As the Earth’s temperature increases due to an increase in the greenhouse effect, this can lead to…?

A

climate change

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17
Q

Some fuel is burnt to heat water. Describe the energy transfer that takes place. Use the word “store” and “pathway”

A

The chemical store of the fuel is transferred to the thermal store of the water via the heating pathway.

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18
Q

Water in a reservoir falls and drives a turbine which spins. What is wrong with the following description of the energy transfer:
Gravitational potential store to kinetic store

A

You need to specify the object the store is associated with e.g. the gravitational store of the water is transferred to the kinetic store of the water as it falls, which is transferred to the kinetic store of the turbine.

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19
Q

How do you calculate energy efficiency?

A

Efficiency = 100 x useful output/total input

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20
Q

What is the golden rule of energy transfers?

A

Energy cannot be created or destroyed. Energy in = energy out.

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21
Q

When will heat transfer occur?

A

When there is a temperature difference between two objects

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22
Q

What is the difference between temperature and the thermal store?

A

The thermal store also takes into account the mass of the substance

23
Q

How do particles move in a warmer substance?

A

Faster (remember temperature is a measure of the average kinetic energy of the particles)

24
Q

Why are solids the best conductors?

A

Particles are closely packed and regularly arranged allowing vibrations to pass from one particle to another easily.

25
Q

Why are metals good conductors?

A

They contain free electrons which can gain energy and travel throughout the material.

26
Q

What are the three types of heat transfer?

A

Conduction, convection, radiation

27
Q

What states of matter can convection occur in?

A

Liquids and gases

28
Q

As you heat a liquid or gas, what happens to the kinetic store of the particles?

A

Increases

29
Q

As you heat a liquid or gas, what happens to the spaces between the particles ?

A

Increases

30
Q

As you heat a liquid or gas, the heated part becomes _________ dense?

A

Less

31
Q

What is wrong with the following statement - “as you heat a substance, the speed of movement of the particles increases and they expand”

A

The particles do not expand. The space between the particles expands.

32
Q

Where do convection currents occur in real life? Give 2 examples

A

Near radiators, in kettles or fluid in a pan on the stove, in the atmosphere, within the Earth’s core, hot air balloons…

33
Q

What is the main difference between radiation and conduction and convection?

A

Conduction and convection rely on particles.

34
Q

What kind of wave is infrared radiation?

A

Transverse

35
Q

If we increase the temperature of an object, what happens to the infrared radiation it emits?

A

It increases

36
Q

Which surfaces are the best emitters and absorbers of radiation?

A

matt black

37
Q

Which surfaces are the worst emitters and absorbers of radiation?

A

Shiny white or silver

38
Q

Why do we use insulators?

A

To reduce unwanted energy transfers by heating

39
Q

List 3 features in a home that can reduce unwanted energy transfers?

A

Draft excluders, double glazing, carpets, curtains, cavity wall insulation, loft insulation, radiator reflectors, fireplace chimney balloons

40
Q

What are the main chemical elements found in plastic?

A

Carbon and hydrogen

41
Q
  1. In a plastic, short chain m__________ are made into long chain p__________. The process is known as _________________________.
A

monomer, polymer, polymerisation

42
Q

Which element (beginning with C ) is the fundamental building block of life?

A

Carbon

43
Q

Name a process that removes carbon dioxide from the atmosphere?

A

Photosynthesis, dissolving atmospheric CO2 into seawater

44
Q

Name 2 processes that add carbon dioxide to the atmosphere?

A

Weathering of limestone, combustion of hydrocarbons, respiration from animals and plants

45
Q

When carbon dioxide dissolves in water, what happens to the pH?

A

It decreases - the water becomes more acidic.

46
Q

By which process does carbon dioxide enter a plant?

A

Photosynthesis

47
Q

Which gas makes up 78% of our atmosphere?

A

Nitrogen

48
Q

Approximately how much oxygen is there in the air we breathe?

A

21%

49
Q

Which layer of the Earth’s atmosphere do we live in?

A

Troposphere

50
Q

What happens to the atmosphere as you gain altitude?

A

It becomes less dense

51
Q

The Sun’s energy reaches the Earth and is ……………………. by the surface. The energy is emitted as …………………. (heat) radiation

A

absorbed. Infrared

52
Q

Give two examples of greenhouse gases

A

water vapour, carbon dioxide, methane and nitrous oxide

53
Q

What do greenhouse gases do?

A

Absorb infrared radiation emitted by the Earth’s surface. This causes the temperature of the atmosphere to increase.

Year 7 Science 23/24 (7 decks)

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