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Physics Year 8 > 1. Energy > Flashcards

1. Energy Flashcards

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1
Q

What is kinetic energy?

A

Kinetic energy is movement energy that keeps something going until it has completely transfered into friction energy, then the object stops.

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2
Q

What is Potential Gravitational energy?

A

Potential gravitational energy is the energy gathered when something is moved further away from the gravity’s centre. It is called potential gravity because it only turns into gravity and then to kinetic energy if the object has been let go of.

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3
Q

What is elastic energy?

A

Elastic potential energy is stored when say you stretch an elastic band, when you let go it travels because the energy that is stored is transferred into kinetic energy.

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4
Q

What is thermal energy?

A

Thermal energy is where there is a difference in temperature between two objects, for example an ice cube on a warm plate. The energy is transferred from the plate to the ice cube until they are both the same temperature. When they are the same temperature it is called a Thermal Equilibrium.

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5
Q

What is Nuclear energy?

A

Nuclear energy is the energy released during nuclear fission or fusion.

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6
Q

What is chemical energy?

A

Chemical energy is the energy where a chemical goes through transformation of a chemical reaction to make energy, for example a battery.

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7
Q

What type of energies are stored energies?

A

Potential:

  • Gravitational potential energy
  • Chemical energy
  • Elastic potential energy
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8
Q

Can you destroy and create energy?

A

No, energy cannot be created or destroyed, only transferred from one form to another. This is called the law of conservation of energy.

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9
Q

Describe the energy transfers in the motion of a swinging pendulum.

A

When a pendulum is pulled back, the further away from the earth’s core it goes the more gravitational potential energy is gained. When you let go of the pendulum, the gravitational energy is transferred into kinetic energy, making the pendulum move.
The pendulum stops because more and more kinetic energy is turning into heat and sound energy because of the friction against the air.

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10
Q

List some renewable types of energy.

A

Hydroelectric, Geothermal, Solar, Wave, Wind, Biomass.

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11
Q

Name some non-renewable types of energy

A

Fossil fuels, nuclear.

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12
Q

Name some temperature scales

A

Celsius, Fahrenheit, Kelvin.

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13
Q

What would the temperature be in Kelvin if it was 0 degrees centigrade.

A

Kelvin = 273K

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14
Q

What would the temperature be in Centigrade if it was 0 Kelvin?

A

Celsius = -273 degrees Celsius

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15
Q

What is the difference between conduction, convection and radiation?

A

Conduction is heat transferring in solids.
Convection is heat transferring in fluids.
Radiation is heat transferring but it doesn’t need to pass through particles.

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16
Q

How is energy transferred by conduction (non metals)?

A

Energy is transferred when particles are heated so they vibrate more and bump into the neighbouring particles and the neighbouring particles gain kinetic energy and vibrate more themselves. This repeats and passes energy through the solid.

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17
Q

How is energy transferred by convection?

A

When fluids (liquids and gases) are heated the particles gain kinetic energy and move about more, this causes them to spread out and become less dense. Since the fluid is less dense it will rise and it will take the extra energy with it. The more dense fluid will fill the gap, and the process repeats.

18
Q

How is energy transferred by radiation?

A

Hot objects radiate heat, and cooler objects absorb it. Some surfaces absorb and radiate better than others, such as rough surfaces absorb and radiate better but shiny surfaces are bad.

19
Q

How is energy transferred by conduction (in metals)?

A

When a metal is heated, particles vibrate and the electrons travel taking kinetic energy with them, bumping into other particles heating them as well. The atoms also bump into each other passing on the kinetic energy as well.

20
Q

What are the advantages of geothermal energy?

A
  • It is renewable
  • It is efficient
  • Low maintenance
  • Doesn’t produce much pollution
  • It doesn’t depend on weather
  • The water heated can be used to warm housing, so it doesn’t need to be cleaned
21
Q

What are some disadvantages of geothermal energy?

A
  • High upfront cost
  • Electricity needed to pump the water
  • Uses a lot of water
  • Large scale can damage earth’s surface
  • It could damage roots of trees and ruin homes of underground living animals
22
Q

What are some advantages of solar energy?

A
  • It is sustainable
  • It doesn’t use fossil fuels
  • It has a low environmental impact
23
Q

What are some disadvantages of solar energy?

A
  • It depends on weather
  • It doesn’t work at night
  • It uses a lot of land space
  • It uses some rare materials
24
Q

What are some advantages of hydroelectric energy?

A
  • It is renewable
  • It doesn’t use fossil fuels
  • It is reliable
  • It is flexible
25
Q

What are some disadvantages of hydroelectric energy?

A
  • Damages the environment
  • High cost
  • Droughts can higher the electricity prices
26
Q

What are some advantages of wave energy?

A
  • It is renewable
  • It is reliable
  • It is clean
  • It is efficient
  • It doesn’t depend on weather or season
  • It doesn’t need to be on land so it doesn’t use fields that could be used for other purposes
27
Q

What are some disadvantages of wave energy?

A
  • It could damage the environment
  • Rather expensive
  • It is new, so prices will go down when it gets older
28
Q

What are some advantages of wind energy?

A
  • Wind is free
  • Renewable
  • Can be very effective
  • Can be done off shore, so not over crowding fields that could be used for other purposes
  • Space efficient
29
Q

What are some disadvantages of wind energy?

A
  • Not reliable
  • High upfront cost
  • Bad for the environment
30
Q

What are some advantages of biomass energy?

A
  • Renewable
  • Carbon Neutraliser
  • Cost effective
31
Q

What are some disadvantages of biomass energy?

A
  • Uses lots of space
  • Can be very expensive
  • Some land isn’t right to use
32
Q

What is elastic limit?

A

Elastic limit is the maximum extent to which a solid may be stretched without permanent alteration to size and shape.

33
Q

How could you speed up a heat transfer by conduction?

A

Use a solid, preferably a metal. Dense materials because the particles collide more easily.

34
Q

How could you slow down a heat transfer?

A

Use a material that traps a layer or pockets of air because gases don’t conduct heat, e.g. expanded polystyrene and wool.

35
Q

How does temperature difference lead to an energy transfer?

A

When two or more substances have a temperature difference, the energy is transferred from the hotter substance to the cooler substance until they are the same temperature. This is called a thermal equilibrium.

36
Q

How could you speed up a heat transfer by convection?

A

Use a fluid and make sure it can move.

37
Q

How do you slow down a heat transfer by convection?

A

Put the fluid into a container with small compartments, so the fluid can’t move around and spread heat.

38
Q

How could you speed up a heat transfer by radiation?

A

The object you want to radiate heat needs to be a dark colour, like black and it needs to be mat.

39
Q

How can you slow down a heat transfer by radiation?

A

The object that you don’t want to radiate heat needs to be light or silvery and shiny.

40
Q

What is Hooke’s Law?

A

Hooke’s law shows that the amount an object stretches is proportionate to the amount of weight applied.

Physics Year 8 (2 decks)

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