Energy Flashcards

1
Q

What does it mean when an energy is transferred usefully?

A

Energy that is transferred usefully is transferred into the store that you wanted to go to

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2
Q

Why is this dissipated is energy described as wasted

A

Dissipated energy is sometimes be described as we said because the energy has been transferred into stores that are not useful

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3
Q

In a close system, what is the effect of energy transfers on the total energy of the system?

A

In a closed system energy transfers have no effect on the total energy of the system and example of this is a cold spoon being dropped into an insulated flask containing hot liquid. Once the flask is sealed, flask the liquid on the spoon form a closed system. Energy is transferred by heating from the thermal store of the liquid to the thermal energy store of the spoon.

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4
Q

What does it mean If a machine is powerful

A

A powerful machine is a machine that can transfer a lot of energy in a short space of time

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5
Q

Describe how the cooling rate of a building relates to the thickness of its wall

A

The thick of the walls of the building, the slower the building will cool

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6
Q

What experiment can Kate do to investigate house thickness of bubble wrap affects how good thermal insulator is

A

Parramatta boiling water into a bigger wrapped in one layer of bubble wrap

Place the lid on the beaker and insert a thermometer through a small hole in the lid. When the water reaches a certain value, start a timer after a set amount of times, measure the temperature change. Repeat with different layers.

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7
Q

Name three main fossil fuels

A

Call oil and natural gas

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8
Q

Name, renewable energy sources

A

The Sun, wind, water waves, hydroelectricity, biofuel, tides, geothermal

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9
Q

Compare the advantages and disadvantages of renewable and non-renewable

A

ADVANTAGES
-renewable energy sources never run out
-They do less damage to the environment

DISADVANTAGES
-Renewable energy resources tend not to provide as much energy and can’t be less reliable as they often depend on the weather

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10
Q

What material can make biofuels?

A

Plant products or animal poo

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11
Q

Geothermal energy can be used to heat water. State the energy stores that energy is transferred from onto when harnessing geothermal energy.

A

Energy is transferred from thermal store of the Underground rocks to the thermal energy store of the water

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12
Q

Is hydroelectric power, reliable

A

It is reliable, except in times of drought. Water can be allowed through to Barns to provide an immediate response to demand for electricity

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13
Q

How come hydroelectric power impact the environment

A

It requires flooding of the valley rotor vegetation that emit greenhouse gases and The destruct habitats

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14
Q

Why are fossil fuels currently reliable?

A

They can be extracted from the Earth at a fast enough rate, the power plants always have enough fuel in stock to meet them demand.

However, they are slowly running out, so in the future, they will be harder to obtain

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15
Q

Advantages of nuclear power

A

ADV
-MORE ENVIRONMENTALLY FRIENDLY
-Doesn’t directly a myth, sulphur dioxide, a greenhouse gases

DISADV
-Nuclear waste produced is dangerous and difficult to dispose
Risk of nuclear catastrophe

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16
Q

Describe how fossil fuels contribute to global warming

A

They emit carbon dioxide and other greenhouse gases into the atmosphere. When they opened this adds to the greenhouse effect and contributes to global warming.

17
Q

How do you fossil fuels impact the environment?

A

Burning, coal or oil, release is sulphur dioxide which causes acid rain, and this is harmful to trees and soils.

Coal mining also ruins, landscapes and oil spillages can affect mammals and birds living in and around the city

18
Q

Why are biofuels fairly reliable?

A

Crop to use, take a relatively short time to grow. A different crops can be grown all year round.. they can be stored for when they are needed to provide a reliable energy resource

19
Q

Compare, reliability of tidal, and solar

A

Both reliable
Solar power can generate electricity, even when it is cloudy
Tidal power relies on the tide, which always occurs twice daily and are close to their predicted heights

Power output from both resources will vary with external factors and output cannot be increased on demand

20
Q

Why has electricity use decreased this century?

A

Appliances are becoming increasingly efficient, and people are becoming more careful with energy use in their homes

21
Q

Why has electricity use decreased this century?

A

Appliances are becoming increasingly efficient, and people are becoming more careful

22
Q

Give two reasons why governments are keen to use more renewable energy resources

A

They have a less negative impact on the environment
They will run out one day
Other countries and public or exerting pressure to shift towards renewable

23
Q

Why can’t they switch from using non-renewable suddenly?

A

They are less reliable and cannot increase power output on demand. Researching ways to improve reliability takes time.

24
Q

Kinetic energy

A

Energy stored in moving objects, if it has no movement it has no kinetic energy

Eg car. Chemical energy store of petrol, turns into kinetic energy

25
Q

Elastic potential energy

A

When a spring is stretched we apply a force to change the length. This is called doing work. Energy in to stretch spring is called elastic potential energy.

Directly proportional to force. If we apply too grater. There is no longer directly proportional. The spring has been stretched upon limit of proportionality

26
Q

Gravitational potential energy

A

Energy stores in an object due to its position above the earth. Force of gravity acting on an object.

Chemical energy in muscles transfering to gravitational energy in ball as a ball lifter above the ground.

27
Q

Law of conservation

A

Energy cab be transferred usefulky , stored or dissapated but cannot be created or destroyed

28
Q

Systems

A

Object or group of objects that interact

Open system energy and matter can be transferred to and from

Closed system energy but not matter

Isolated systems not energy not matter

29
Q

Pendulum

A

Friction causes energy to be transferred to thermal store. Less useful so energy dissipated and wasted

GPE transfers to KE maximum KE of mass (middle) and maximum GPE of mass again. Causes to swing

30
Q

Bungee jumper

A

As jumper falls, energy is transferred from GPE to KE . When bunjee rope starts to tighten, KE is maximum. When rope fully extended, KE is zero because not moving. KE is transferred to elastic potential energy of rope

The bunjee recoils and energy is transferred back to EK. Finally at the top of ascent, ke is transferred to gpe.

Jumper never turns back to origional position because energy is dissipated to the surrounding as thermal. Due to friction.

31
Q

Work done

A

When energy is transferred from one store to another.

Mechanical - force to move object
Electrical work - involves current transferring energy

Force x distance

32
Q

Car brakes

A

Car is moving has a kinetic store.
Driver press on brake, brake presses against wheel. Creates friction between brake and wheel. Kinetic store of car is transferred to thermal store of brake. Temp of brake increases and car slows and stops.

Kinetic energy of car —> thermal energy of brake

33
Q

Power

A

Rate at which energy is transferred or work is done

1 watt is an energy transferred of 1J per second

34
Q

Efficiency

A

Tells us what fraction of the energy of the appliance is transferred to useful energy

35
Q

How can we increase efficiency

A

Reduce thermal conductivity

36
Q

Thermal conductivity walls

A

The higher the thermal conductivity of a material the higher rate of energy transfer by conduction across the materials

Cavity wall insulation has a very low thermal conductivity reduces overall thermal conductivity

37
Q

Thermal conductivity windows

A

Double glazed low thermal conductivity

Particles further apart so less collisions so less thermal energy

38
Q

Roof

A

Loft insulation