Conservation of Energy

Question 1

How can energy be stored?

Answer 1

Chemically, kinetically, thermally, in elastic potential energy, in gravitational potential energy, and in nuclear energy (in atoms)

Question 2

Ways energy can be transferred?

Answer 2

Forces, electricity, light, sound

Question 3

What is the law of conservation of energy?

Answer 3

Energy cannot be created of destroyed, only transferred from one store to another

Question 4

What unit is energy measured in?

Answer 4

Joules (J)

Question 4

What do sankey diagrams show?

Answer 4

The amount of energy transferred (also can show useful and wasted energy)

Question 5

What to energy diagrams show?

Answer 5

Represents energy stores and transfers in a system

Question 6

Describe changes in stores of energy as car accelerates

Answer 6

As the car accelerates, energy stored kinetically increases and energy stored chemically in fuel decreases

Question 7

What does energy dissipating mean

Answer 7

It means spreading out (wasted)

Question 8

Most machines waste energy when they get hot because of ____

Answer 8

Friction. It is transferred to surroundings by heating and is dissipated and wasted.

Question 9

How can you reduce friction in machines?

Answer 9

Use lubrication like oils, liquids or even some gases

Question 10

How do calculate energy efficiency?

Answer 10

Useful energy/total energy supplied

Question 11

What is efficiency?

Answer 11

How good a machine is at transferring energy into useful forms

Question 12

What does insulation do?

Answer 12

Insulation slows down the rate at which energy is transferred out of a house by heating

Question 13

How can energy by heating be transferred?

Answer 13

Conduction: vibrations passed between particles in a solid
Convection: Hot fluid rising and creating convection currents
Radiation: The only way it can be transferred through a vacuum

Question 14

What does the rate of energy being transferred by heating depend on?

Answer 14

1) Thickness
2) Thermal conductivity
3) Temperature difference

Question 15

What is thermal conductivity

Answer 15

It is the ability of a given material to conduct/transfer heat

Question 16

What is gravitational potential energy?

Answer 16

Energy stored because of objects position in a gravitational field?

Question 17

How do you calculate change in GPE?

Answer 17

🔺 GPE = m * g *🔺h

Question 18

What is kinetic energy?

Answer 18

Energy stored in moving objects

Question 19

How do you calculate kinetic energy?

Answer 19

KE = 0.5 * m * v^2

Question 20

What is a non renewable energy resources

Answer 20

Nonrenewable resources are limited in supply and cannot be used sustainably

Question 21

Give examples of non renewable resources

Answer 21

Coal, oil, gas (fossil fuels)
Nuclear fuels (uranium)

Question 22

Pros and cons of coal and oil

Answer 22

Pros: Cost effective, readily available (for now), easy to get the energy
Cons: will eventually run out, releases CO2, releases sulphur dioxide (acid rain)

Question 23

Pros and cons of natural gas

Answer 23

Pros: Easy to store and transfer, causes less pollution than coal, stations emit less CO2
Cons: Will eventually run out, fracking contaminates water, still releases CO2

Question 24

Pros and cons of nuclear power stations

Answer 24

Pros: No CO2 release, can produce more energy from same mass, less pollution Cons: Expensive to build, hazardous radioactive waste produced which can harm environment, accidents can have serious consequences

Question 25

What is a renewable energy resource

Answer 25

Resources that will not run out and most of them do not cause pollution of CO2

Question 26

5 examples of renewable resources

Answer 26

Solar energy, hydroelectricity, tidal power, wind turbines, biofuels

Question 27

Pros and cons of solar energy

Answer 27

Pros: Doesn't emit CO2 or any pollution, low maintenance, can be used in homes and power stations Cons: Not available all the time (night and cloudy), requires space

Question 28

Pros and cons of wind turbines

Answer 28

Pros: Generates clean electricity as long as wind not to fast or slow so dependable Cons: Many needed to produce same amount as fossil fuels power stations, visual pollution

Question 29

Pros and cons of tidal energy

Answer 29

pros: predictable energy generation because depends on tides which is reliable, efficient because in water less wasted Cons: Can damage underwater life or seabed, has specific site requirements

Question 30

pros and cons of hydroelectricity

Answer 30

pros: generated from falling water and available at any time as long as it doesn't dry up, can be started and stopped very quickly cons: lack of available reservoirs, expensive up front

Question 31

pros and cons of biofuels

Answer 31

Pros: large supply, carbon neutral in theory, biodegradable cons: energy needed to grow and harvest crops so most not really carbon neutral