Energy

What is a system?

An object or group of objects

How can a system be changed?

• Heating

• Work done (forces)

• Work done (electrically)

What is the kinetic energy formula?

Ek = ½mv²

What is the formula of elastic potential energy?

Ee = ½ke²

What is the formula of gravitational potential energy?

Ep = mgh

What is the specific heat capacity of a susbstance?

The amount of energy required to raise 1kg of a substance by 1 degree celsius

What is the formula for specific heat capacity?

∆E = mc∆θ

What is specific latent heat of fusion?

The amounf of energy required to change the state of a substance (solid + liquid)

What is the specific latent heat of vaporisation?

he amounf of energy required to change the state of a substance (gas+ liquid)

What is the formula for specific latent heat?

∆E = mL

What is hooke’s law?

If an object follows hooke’s law, the force used to strech an object is directly proportional to the extension the object has, assuming the object has not reached its limit of proportionality

What is the limit of proportionality?

The limit where if an object is stretched so much, if it were to have all its forces upon it removed it would not return to its original shape

What is conduction?

How heat is transferred through solids, by vibrations that hit other particles and spread, distrubuting heat across the solid

What is convection?

In fluids, heat transfer works as when the fluid is heated its particles move faster and spread out, causing less dense regions of fluid to rise, and denser cooler regions to sink towards the heat source which causes a convection current

What is radiation?

Energy carried in electromagnetic waves, by infrared emitting objects having the infrared radiation absorbed by another object, causing the other objects’ temperature to rise

What is power?

Power is the rate at which energy is transferred or the rate at which work is done

What is the formula for power?

power = energy transferred or work done / time

What is the law of conservation of energy?

Energy can be transferred usefully, stored or dissipated, but cannot be created or destroyed.

What is internal energy?

The total sum of the kinetic energy and potential energy of all the particles inside a system

What is waste energy?

Energy not used for the desired purpose, mainly heat/sound

What is efficiency?

efficiency = energy transfer or power / time

How can we reduce energy waste?

• Lubrication

• Streamlining

• Insulation

What is a renewable energy resource?

An energy resource that is replenished as it is used, or can be replenished.

What is a non-renewable energy resource?

An energy resource that is finite and will eventually run out.

Which energy resources are renewable?

Biofuel, wind, hydroelectricity, geothermal, tides, the Sun and water waves.

Which energy resources are non-renewable?

Coal, oil, gas and nuclear fuel.

What are the three main uses of energy resources?

Transport, electricity generation and heating.

Which energy resources are used for transport?

Mainly fossil fuels and biofuels. Electricity can also be used to power electric vehicles.

Which energy resources can be used to generate electricity?

Fossil fuels, nuclear fuel, biofuel, wind, hydroelectricity, geothermal, tides, the Sun and water waves.

Which energy resources can be used for heating?

Fossil fuels, biofuels and electricity.

What does it mean for an energy resource to be reliable?

It means it can provide energy when it is needed and consistently.

Why are fossil fuels reliable?

They can be burned whenever energy is needed, as long as fuel is available.

Why is nuclear energy reliable?

Nuclear power can generate electricity continuously, regardless of weather conditions.

Why is wind energy less reliable?

It depends on wind speed, so electricity cannot be generated when there is not enough wind.

Why is solar energy less reliable?

It depends on sunlight, so less energy is generated when it is cloudy and none is generated at night.

Why is tidal energy more reliable than wind and solar?

Tides are predictable and occur regularly, although they cannot generate energy continuously.

What is the environmental impact of using fossil fuels?

Burning them releases CO₂, contributing to climate change. They can also release pollutants such as sulfur dioxide, causing acid rain. Extraction can damage habitats.

What is the environmental impact of nuclear fuel?

It produces radioactive waste, and uranium mining can damage the environment. Nuclear accidents can have serious environmental consequences.

What is the environmental impact of biofuels?

Burning them releases CO₂, while growing fuel crops requires land and can cause deforestation, habitat loss and competition with food crops.

What is the environmental impact of wind energy?

Wind turbines produce very little pollution during operation, but can be noisy, affect landscapes and harm birds or other wildlife.

What is the environmental impact of hydroelectricity?

Dams can flood large areas, destroying habitats and affecting fish migration and river ecosystems.

What is the environmental impact of geothermal energy?

It produces low greenhouse gas emissions but can cause local environmental disturbance and can only be used in suitable geological areas.

What is the environmental impact of tidal energy?

It produces very little pollution during operation, but tidal barrages can alter coastal habitats and affect marine ecosystems.

What is the environmental impact of solar energy?

Solar energy produces no direct emissions during operation, but large solar farms require large areas of land, and manufacturing panels requires raw materials and energy.

What is the environmental impact of wave energy?

It produces very little pollution during operation but can affect marine ecosystems and coastal areas.

What is the general trend in the use of renewable energy?

The use of renewable energy has generally increased.

Why has the use of renewable energy increased?

Because of concerns about climate change, the finite supply of fossil fuels, improvements in technology and attempts to reduce CO₂ emissions.

Why are fossil fuels still widely used?

They are reliable, have existing infrastructure and can be used for transport, electricity generation and heating.

What can science do about environmental issues caused by energy resources?

Science can identify and measure environmental problems, investigate their causes and develop possible solutions.

Why can't science always solve environmental issues caused by energy resources?

Decisions are also affected by political, social, ethical and economic factors.

How can economic factors affect the choice of energy resource?

A cleaner energy source may not be chosen if it is too expensive compared with other options.

How can political factors affect the choice of energy resource?

Governments and political decisions can influence which energy resources are supported and developed.

How can social factors affect the choice of energy resource?

People may oppose energy projects because of concerns about noise, appearance, jobs or effects on their local area.

How can ethical factors affect the choice of energy resource?

People may disagree about whether the benefits outweigh environmental risks, such as radioactive waste or habitat destruction.

What is an important limitation of science when dealing with energy resources?

Science can identify environmental issues, but it does not always have the power to deal with them because decisions also depend on political, social, ethical and economic considerations.