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Year 8 Science > Energy > Flashcards

Energy Flashcards

1
Q

What is the law of conservation of energy?

A

The law that states that energy cannot be created or destroyed only transferred.

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2
Q

What are light, sound and electricity examples of?

A

Ways to transfer energy between stores.

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3
Q

What does the thermometer measure and in what unit?

A

It measures heat in degrees celsius (°C)

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4
Q

What does temperature measure?

A

Average thermal energy.

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5
Q

What is thermal energy?

A

The total energy in heat.

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6
Q

What has more thermal energy a warm bath or a kettle.

A

The bath. Although a kettle has more heat, as the bath needs more heat to be transferred to be as hot as the kettle due to its volume it is spread out evenly through the liquid until it reaches an equilibrium.

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7
Q

What happens when you heat particles?

A

They gain kinetic energy and vibrate or more faster.

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8
Q

Why can the amount of energy needed to heat something vary?

A

Due to different masses, material (conductivity) and how much it needs to rise.

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9
Q

What is an equilibrium?

A

When an object has the same thermal energy throughout the entire object.

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10
Q

What is a renewable fuel?

A

A fuel that will never run out. It only produces greenhouse gases when built, not whilst being used.

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11
Q

What are the different renewable fuels?

A

Wind, tidal, wave, hydroelectric, geothermal, biomass and solar power.

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12
Q

What is a non-renewable fuel?

A

A fuel that cannot be used sustanibly and will run out.

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13
Q

What are the different non-renewable fuels?

A

Fossil fuels: Crude oil, coal and natural gas.
Nuclear

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14
Q

How do fossil fuels provide energy?

A
  1. Fossil fuels burnt to heat water which turns to steam.
  2. Steam turns a turbine which spins a generator.
  3. The current is sent to different buildings through cables along the national grid
  4. The fossil fuels produce greenhouse gases, such as carbon dioxide.
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15
Q

What are the different ways thermal energy is transferred?

A

Conduction, convection or radiation.

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16
Q

What is conduction?

A

When particles vibrate due to being heated transferring heat through hitting other particles making them vibrate. It happens in solids.

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17
Q

What is convection?

A
  1. The part closest to the heat heats up moving faster causing them to move further apart and decreasing in density.
  2. As it it less dense than the colder particles, it rises
  3. The colder particles go to the bottom and heat up gaining speed causing them to move further apart and decreasing in density.
  4. The hotter particles rise to the top cool down and go back to the source of heat and the cycle repeats.
    It occurs in gases and liquids.
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18
Q

What is power?

A

The rate of energy transfer - how much energy is transferred each second.

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19
Q

What are energy bills measured in?

A

kilowatts per hour (kWh)

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20
Q

How do you convert Watts into joules

A

Power (watts) X time (seconds)

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21
Q

How do you convert energy into power?

A

Energy (joules) divided by time (seconds)

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22
Q

What are some ways to reduce energy bills?

A
  • Using fewer appliances or more efficient ones
  • Insulated houses lose less thermal energy so less power would be neededto be used to heat up the house.
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23
Q

How is work done (j) calculated?

A

Force (N) X distance (m)

24
Q

How is force calculated if you have the numbers for work done and distance?

A

Work done (j) divided by distance (m)

25
Q

What is a simple machine?

A

A machine that makes it easier to do work but you still get the same energy out that you put in.

26
Q

What is infrared radiation?

A

The waves that transfer energy without needing particles

27
Q

Which objects emit radiation?

A

All of them.

28
Q

What determines how much radiation is absorbed in something?

A

Which colour - brighter colours absorb less radiation darker colours absorb more.
How smooth or rough - smoother objects reflect more and absorb less, rougher object absorb more.

29
Q

What is chemical energy?

A

Energy that is stored in batteries, fuels and food.

30
Q

What is energy measured in?

A

Joules (j)

31
Q

Which activities need more energy?

A

Activities that require longer or more intense use of the muscles.

32
Q

What determines the amount of energy in a food?

A

The amount of carbohydrates - starchy and simple sugars or the amount of lipids and protein.

33
Q

What does absorb mean?

A

To take something in

34
Q

What is a chemical store?

A

A store of energy in batteries, fuels or food.

35
Q

What is a convection current?

A

The movement of hot particles rising, cooling down and falling and heating rising up and cooling and falling etc.

36
Q

What is a fossil fuel?

A

A fuel that is from the remains of a living thing after millions of years of high pressure and anerobic conditions.

37
Q

What is a gear?

A

A simple machine used on bikes to multiply the force used to get somewhere.

38
Q

What is a greenhouse gas?

A

A gas that traps hot air within the atmosphere heating it up.

39
Q

What is infrared radiation?

A

The radiation as a wave that carries thermal energy with it.

40
Q

What is an insulator?

A

A material that is not very conductive and keeps thermal energy or electrical energy in or out.

41
Q

What is a joule?

A

The unit used to measure energy.

42
Q

What is a kilowatt?

A

A thousand watts, it is used to measure power.

43
Q

What is kinetic energy?

A

The energy stored in a moving object.

44
Q

What is a lever?

A

A simple machine used to make lifting things easier.

45
Q

What is a power station?

A

The place where energy is turned in to electricity.

46
Q

What does reflect mean?

A

To bounce something off its surface.

47
Q

What is thermal energy?

A

The energy store of heat.

48
Q

What is a thermometer?

A

The tool used to measure thermal energy.

49
Q

What is work done?

A

Work done is the energy used to move or change an object.

50
Q

What are all of the energy stores?

A

Elastic potential, gravitational potential, kinetic, magnetic, thermal, chemical, electrostatic, nuclear

51
Q

What are the different energy transfers?

A

Mechanically, By heating, by radiation, electrically

52
Q

Where is coal formed?

A

Plants

53
Q

Where are crude oil and natural gas formed?

A

Marine organisms

54
Q

What type of energy does an object have if it has an electrical charge?

A

Electrostatic

55
Q

When is energy transferred by radiation?

A

When a light bulb or an LED transferes visible light and infrared radiation

Year 8 Science (3 decks)

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