Energy Resources and Energy Transfers

what are all of the energy stores?

Thermal, kinetic, chemical, elastic potential, magnetic, gravitational potential, electrostatic, nuclear

what are the different energy transfers?

heating, electrical, radiation (light and sound), mechanical

what is the principle of conservation of energy?

energy cannot be created or destroyed, only transferred from one store to another

how does thermal energy transfer take place in conduction?

in solids the particles vibrate more when heated

they pass energy to neighbouring particles

in metals, free electrons also carry energy quickly

how does thermal energy transfer take place in convection?

in liquids and gases, the heated fluid expands and becomes less dense

it rises while the cooler fluid sinks

this creates a convection current

how does thermal energy transfer take place in radiation?

in any state, energy is transferred as infrared electromagnetic waves

no particles are needed

give three examples of convection in everyday life

heating a room (radiator)

boiling water

hot air balloons

what are the two things that affect how well infrared radiation emits or absorbs something?

surface (colour + texture)

temperature

what is an example of a good absorber and emitter?

black, dull (matt) surfaces

what is an example of a poor absorber and emitter?

white, shiny (reflective) surfaces

what is the effect of temperature on infrared radiation?

the hotter an object is the more infrared radiation it emits

the faster it loses thermal energy

describe the method for a conduction practical

take a metal rod

attach wax + drawing pins on it

heat one end with a bunsen burner

pins fall of one by one, starting closest to flame

describe the method for a convection practical

fill beaker with water

add small amount of potassium manganate

heat gently underneath

purple colour rises, circulates then sinks

describe the method for a radiation practical

use a container with different surfaces (dull black, shiny)

fill with hot water

use a thermometer or infrared detector

black surface loses heat fastest, shiny surface loses heat slowest

give two examples of ways to reduce conduction

loft insulation in houses

foam in walls

give two ways to reduce convection

double glazing (air gap between glass panes)

cavity wall insulation

give two ways to reduce radiation

shiny foil in a vacuum flask

reflective surfaces behind radiators

what is work done equal to?

energy transferred

what is power?

the rate of transfer of energy

what is the energy transfers when generating electricity using wind power?

kinetic energy of wind turbine turns blades

turbine spins a generator

—> electrical energy

what is the energy transfers when generating electricity using water power?

gravitational potential energy of water stored at height

water falls—> kinetic energy

spins turbine—> electricity

what is the energy transfers when generating electricity using geothermal energy?

Thermal energy from Earth’s core heats water

Steam rises → kinetic energy of steam

Turns turbine → electricity

what is the energy transfers when generating electricity using solar heating systems?

Radiation from Sun → thermal energy

Heats water directly

Hot water can produce steam → turbine → electricity

what is the energy transfers when generating electricity using solar cells?

Light energy (photons) from Sun

Directly converted into electrical energy

what is the energy transfers when generating electricity using fossil fuels?

Chemical energy stored in fuel

Burning → thermal energy (heat)

Boils water → steam → kinetic energy

Steam spins turbine→ electricity

what is the energy transfers when generating electricity using nuclear power?

Nuclear energy (fission of uranium)

Releases thermal energy

Heats water → steam → turbine → electricity

what are two advantages and disadvantages of wind power?

advantages: renewable, no fuel cost

disadvantages: noisy pollution, large land area needed

what are two advantages and disadvantages of hydroelectric power?

advantages: renewable, no fuel cost

disadvantages: expensive to build, limited suitable locations

what are two advantages and disadvantages of geothermal energy?

advantages: renewable, low emissions

disadvantages: expensive drilling, only possible in certain regions

what are two advantages and disadvantages of solar power?

advantages: renewable, no fuel cost

disadvantages: only works in daylight, weather dependent

what are two advantages and disadvantages of fossil fuels?

advantages: high energy output, cheap infrastructure

disadvantages: non-renewable, produces CO₂ —> climate change

what are two advantages and disadvantages of nuclear power?

advantages: very high energy output, very low CO₂ emissions during operation

disadvantages: radioactive waste, risk of accidents

what are the renewable and non-renewable resources

renewable: wind, solar, hydro, geothermal

non-renewable: fossil fuels, nuclear