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Year 8- Science > Energy And Energy Transfers > Flashcards

Energy And Energy Transfers Flashcards

1
Q

What is the law of conservation of energy?

A

Energy can neither be created nor destroyed-only transferred (from one type to another)

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2
Q

What is energy measured in?

A

In joules (J). One joule i a very small amount of energy, so we often use kilojoules (KJ). 1 kilojoule = 1000 J

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3
Q

Name three examples of fuels?

A

Food like chocolate, coal and wood

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4
Q

What do fuels need so that they can be burned and used?

A

Oxygen

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5
Q

What type of store does food, fuels and batteries get stored in?

A

Chemical store

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6
Q

What type of store does hot objects get stored in?

A

Thermal energy

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7
Q

What type of store does moving objects get stored in?

A

Kinetic energy

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8
Q

Energy to do with position in a gravitational field is stored in a…

A

Gravitational potential store

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9
Q

What type of store does changing shape, stretching or squashing get stored in?

A

Elastic store

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10
Q

Is the total energy before an action the same as afterwards?

A

Yes

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11
Q

State three ways that energy is transferred between stores?

A

Electric current, light, and sound are ways of transferring energy between stores

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12
Q

What does it mean if energy has been dissipated?

A

For example energy is transferred to the thermal store of the surroundings rather than the store that you want it to go to

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13
Q

What is temperature?

A

the degree or intensity of heat present in a substance or object, especially as expressed according to a comparative scale and shown by a thermometer or perceived by touch.

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14
Q

What do you measure temperature in?

A

We measure temperature in degrees Celsius (°C)

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15
Q

What is a thermometer?

A

You use a thermometer to measure temperature. Some thermometers have a liquid inside a very thin glass tube that expands when it is heated. Other thermometers are digital

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16
Q

What happens when you heat things up?

A

Heating changes the movement of particles. If you heat a solid the particles vibrate more. If you heat a liquid or a gas the particles move faster and vibrate more.

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17
Q

What does the energy that you need to increase the temperature of a material depend on?

A
  1. The mass of material
  2. What the material is made of
  3. The temperature rise that you want
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18
Q

What is meant by equilibrium?

A

Equilibrium means when two of the same forces, such as temperature, have the same or equal energy.

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19
Q

What is a conductor?

A

A material that allows the flow of electricity or heat. A metal is a good conductor of energy.

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20
Q

What is conduction?

A

When something like energy is transferred through something very quickly.

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21
Q

How can energy be transferred?

A

Energy can be transferred by conduction, convection, or radiation

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22
Q

In conduction how do particles transfer energy?

A

By colliding with other particles when they vibrate

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23
Q

What is an insulator?

A

Energy is not transferred very easily through materials like wood. Wood and many non-metals are poor conductors. They are insulators. This doesn’t mean they don’t conduct at all but energy is transferred very slowly through them.

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24
Q

What is the best at insulating, solids, liquids or gases?

A

Solids are best at insulating, then liquids and finally gases

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25
Q

What is a convection current?

A

when there is a significant difference in temperature between two parts of a fluid. When this temperature difference exists, hot fluids rise and cold fluids sink, and then currents, or movements, are created in the fluid.

26
Q

What is radiation?

A

Radiation comes from the sun. The sun emits lots of different types of radiation, including light and infrared. Both light and infrared radiation travel as waves

27
Q

How can you transfer energy by radiation?

A

Light and infrared reach the Earth from the Sun by travelling through space. Space is a vacuum and there are no particles. Instead light and infrared travel through waves

28
Q

What does the type of radiation that something or someone emits depend on?

A

The type of radiation that they emit depends on its temperature.

29
Q

What does the amount of radiation something or someone emit per second depend on?

A

How much radiation they emit per second depends on the type of surface

30
Q

How can infrared travel?

A

Infrared can be transmitted, absorbed, or reflected, just like light

31
Q

Name two sources of infrared radiation?

A

The Sun and fire

32
Q

Name two things that can detect infrared radiation?

A
  1. A thermal imaging system

2. A remote thermometer contains a sensor that detects infrared

33
Q

State what happens when infrared hits a white or shiny surface?

A

Light coloured and shiny surfaces reflect infrared.

34
Q

State what happens when infrared hits a dark surface?

A

Dark colours and dark materials absorb more infrared and therefor get hotter a lot quicker

35
Q

Give three examples of fossil fuels?

A

Coal, oil and gas are fossil fuels

36
Q

What are fossil fuels?

A

a natural fuel such as coal or gas, formed over millions of years from the remains of living animals, trees and plants. It is stored in the ocean and under the ground

37
Q

What are energy resources?

A

An energy resource is something that can produce heat, power life, move objects, or produce electricity, for example fossil fuels are an energy resource.

38
Q

Are fossil fuels (coal, oil and gas) non-renewable?

A

Yes

39
Q

What does non-renewable mean?

A

It doesn’t mean that you cant use them again but instead means that you cannot easily get more of them when they run out.

40
Q

What do thermal power stations burn?

A

Thermal power stations burns coal and gas to create power and electricity.

41
Q

What is oil used for?

A

Oil is mainly used to produce petrol, plastics, and other useful materials.

42
Q

How does a power station work and create electricity?

A

A fuel, like coal, is burned to heat up water and produce steam. The steam drives a turbine, which is like a big fan. The turbine drives a generator. This provides the push so that a current flows which is sent out of the power station and to homes and places where it is needed.

43
Q

What does burning fossil fuels produce?

A

It produces a lot of carbon dioxide, which is a greenhouse gas, so it can contribute to climate change. It also produces pollutants like sulfur dioxide, nitrogen oxides, and particulates which are also greenhouse gases.

44
Q

What is a renewable source of energy?

A

It is a resource that is renewable because they will not run out. Many renewable resources come from the nuclear store of energy of the sun.

45
Q

Give examples of renewable energy resources?

A

1.A wind turbine 2.Tidal power 3.Biomass energy 4.Solar cells(solar power) 5.Hydroelectric power 6.Geothermal power

46
Q

How does a wind turbine create electricity?

A

A wind turbine spins a generator directly.

47
Q

How does tidal power create electricity?

A

Tidal: water flows through turbines as the tides goes in and out. The waves turn a turbine which creates electricity.

48
Q

How does biomass energy create electricity?

A

Biomass: you can burn plants instead of coal in a power station. The plants use carbon dioxide when they grow.

49
Q

How do solar cells/panels (photovoltaic) create electricity?

A

Solar cells are able to generate a potential difference from the suns light.

50
Q

How does hydroelectric power create electricity?

A

Hydroelectric: water falls down through turbines in a dam.

51
Q

How does geothermal energy create electricity?

A

Geothermal: hot rocks in the Earth heat water to form steam, which turns turbines.

52
Q

Do renewable energy resources create any carbon dioxide?

A

Renewable resources do not produce much carbon dioxide when they produce a current. They do produce carbon dioxide when they are being built.

53
Q

What is the power rating in for electrical appliances like a microwave(what is the unit of power?)?

A

Watts (W)

54
Q

What does a power rating tell you?

A

The power rating tells you how much energy is transferred per second, or the rate of transfer of energy.

55
Q

What is the equation that tells you how to calculate power (W)?

A

Energy (J)
Power (W)=————-
Time (s)

Or= Watts=Amps X Volts

56
Q

How do you keep an object at the same temperature?

A

To keep an object at the same temperature you need to transfer energy to it at the same rate as energy is being transferred from it.

57
Q

What unit can you measure energy us in for an electricity bill?

A

Kilowatt hours (KWh), or joules, which is the unit that electricity companies use to calculate your bills.

58
Q

State the equation for calculating work?

A

Work done (Joules) = force(newtons) X distance(meters)

59
Q

What two simple machines make it easier to do work by either making the force or distance larger or smaller?

A

A lever and gears

60
Q

How is energy transferred in solids, liquids and gases?

A

Solids-conduction

Liquid and gases-convection

Year 8- Science (6 decks)

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