04 Energy Transfers and Resources Flashcards
Describe the properties of heat radiation.
- it travels in straight lines
- it can travel through a vacuum
- it can reflect off surfaces
- it is an electromagnetic wave much like light
- it travels at the speed of light
- it is a transverse wave
Using the Sankey diagram calculate the efficiency of a thermal power station
1000 J = one large square
200 J = each small square
Useful transfer of Energy Out = 9 small squares
1800J of energy useful transferred electrically out of thermal power station
1800 J/ 5000J = (3600/ 10 000J) x 100 = 36%
Give an example of a chemical store
battery
coal- fuel
food
Give an example of a nuclear store
Uranium in a nuclear power station
Fusion occurring in the Sun
Solids are good conductors
Liquids and gases do not conduct heat well but they do convect heat easily, why?
Liquids and gases have particles which are further apart and have weak forces between them- poor conductors
Liquid and gases have particles can move freely
Convection occurs when particles gain energy (heat up) expands and move from hot to cold regions
Name the energy store depleted and filled when a roller coaster accelerates down the first slope.
Gravitational store of the roller coaster is being depleted
Kinetic store of the roller coaster is being filled along with the thermal store of the track, wheels and surroundings.
Energy is also shifted/transferred away via radiation of sound
Why are metals good conductors of heat
Conduction occurs when heat is transferred through a material from particle to particle
Metals have free electrons which help heat transfer through the metal from particle to particle
What is the law of conservation of energy?
Energy cannot be created nor destroyed, only transferred from one store to another.
Which energy store is depleted in a tidal barrage and how is it transferred away from this store?
Gravitational store of water is depleted
This is transferred mechanically to the kinetic store of the water via the force of gravity
How does heat travel from the hot stove to a potato in the water?
Conduction from the stove to the metal pan- they are in contact
Conduction through the metal pan
Conduction from the pan to the water- they are in contact
Convection to the potato- hot water expands (is less dense) and rises
Conduction through the potato
What are the disadvantages of wind power?
- you need a large area and a large number to replace one power station
- it is not reliable- no wind, no power
- they are a danger to birds on land and boats if in the sea
- they are loud and some say unsightly
Why are solids better conductors of heat than liquids and gases?
Conduction occurs when heat is transferred through a material from particle to particle
In solids, the particles are close together and the forces between particles are stronger.
What are the disadvantages of nuclear power?
- non-renewable source
- creates radioactive waste which takes thousands of years to decay to a safe level
- expensive to build, maintain and decommission
- the possibility of a meltdown causing environmental damage
Which thermometer will record the highest temperature?
The thermometer on the left nearest the matt black surface.
The hot metal radiates heat to the surroundings but the matt black surface will radiate heat at a quicker rate.
What are the advantages of coal, oil or gas power stations?
- they are reliable- produce a constant supply
- much of the existing infrastructure is set-up for fossil fuels
- at them moment fossil fuels are relatively cheap
The thermal store of this cup of tea is depleting or emptying
How is energy transferring or shifted from this cup of tea?
by heating
Use the conservation of energy to work out how much energy is used for respiration in a cow.
Conservation of energy is energy cannot be created nor destroyed, it is only transferred from one store to another.
100kJ = Energy In
4kJ + 63kJ + ? = Energy Out
33kJ of energy goes to respiration in the cow
What are the advantages of wind power?
- renewable energy source
- does not use fossil fuels
- does not produce carbon dioxide or other pollutants
How is energy shifted/transferred from the power station usefully and wastefully?
Usefully- Electrically via wires
Wastefully- Heating from furnace, wires and cooling towers
Radiated as sound from generator
Radiated as light from furnace
Give an example of a kinetic store
car, moving
spaceship, moving
bullet moving
generator turning
The fleece reduce heat loss in two ways? Explain
The fleece traps air
air is a poor conductor- reduces heat loss by conduction
air cannot move- no convection currents set up- reduces heat loss by convection
What are the disadvantages of a hydroelectric power station?
- flooding of valleys and loss of habitats
- can only be built in areas which are mountainous.
- flooding of valleys and displacement of communities
- expensive to build
How does energy transfer or shift from the chemical store of a battery to the thermal store of a bulb?
Electrically- charge moves in wires
Which container will heat up the quickest?
The matt black container
Matt black surfaces are good absorbers of heat radiation
Shiny silvery surfaces will reflect heat radiation
Give an example of a thermal store
hot pan
hot water in a kettle
the filament in a toaster
a human body
What are the 8 stores of energy?
Chemical
Thermal
Gravitational
Kinetic
Vibrational
Nuclear
Electrostatic & magnetic
Elastic
How does energy transfer or shift from a stretched elastic in a catapult to moving stone?
mechanically- elastic exerts a force on the stone
- Elastic store of elastic is emptied*
- Kinetic store of stone is filled*
What energy store is depleted and which energy store is filled when the popper toy is release.
How is this energy transferred from one store to another?
Elastic store of popper toy is depleted
Kinetic store of popper toy is filled
This energy is transferred mechanically via a spring force
How is energy wastefully shifted/transferred from the wind turbine
Energy is wastefully shifted/transferred from the wind turbine via radiation (sound) and heating from wires and generator
What energy store does biomass possess?
Chemical store
Give an example of electrostatic & magnetic energy store
(one of each!)
Electrostatic
Two similarly charged particles near each other
Charged van de Graaf generator
Magnetic
North and north pole of a magnet pushed together
North pole of a magnet and south pole of an electromagnet pulling in a speaker cone
What is the equation for efficiency?
How is energy shifted/transferred usefully from the gravitational store of the water behind the dam to a town nearby?
mechanically from gravitational store of water to the kinetic store of the water
mechanically from the turning turbine to the turning generator
electrically from the turning generator via the wires to the nearby town
How does energy transfer or shift from the nuclear store of the Sun to the chemical store of a rechargeable cell in the international space station
Via radiation through space (EM radiation)
Electrically through wires from solar cell
In an experiment to test the insulating properties of different materials, what is the independent and dependent variable?
independent- I change
dependent- what you measure
Independent variable - type of material wrapped around the copper can
Dependent variable- temperature difference of water after a set amount of time
How does energy transfer or shift from a stretched elastic in a catapult to moving stone?
mechanically- elastic exerts a force on the stone
- Elastic store of elastic is emptied*
- Kinetic store of stone is filled*
Which energy store is being depleted when the wind turbine turns?
Kinetic store of the wind
What store of energy does this boulder possess?
Gravitational store
How does energy transfer or shift from steam in a power station to kinetic store of a turbine turning?
Mechanically- there is a force on the turbine which makes it turn
In an experiment to test the insulating properties of different materials, what are the control variables
Control variables- what is kept the same to keep a fair test.
- volume of water- all 100ml
- initial temperature of water- all 90°C
- thickness of material- all 5mm
- type of can- all copper metal with the same thickness
- lid- all containers have a lid of same thickness and material
- same type of liquid- water
What are the advantages of a hydroelectric power station?
- renewable energy source- does not use fossil fuels
- does not produce CO2 or pollutants
- reliable- energy transferred at a constant rate
- can be turned off when not needed
- the lake created behind the dam can be used for sport and recreation
How is energy shifted/transferred from the gravitational store of the rollercoaster to kinetic store of the rollercoaster as it accelerates down the slope?
Energy is shifted mechanically by the force of gravity
What energy store is being depleted in a nuclear power station?
How is this energy usefully transferred to the nearby town?
Nuclear store of the uranium is being depleted.
The energy is transferred electrically to the nearby town.
What energy store does this hot cup of tea have?
Thermal store
What energy store is depleted and which energy store is filled when the popper toy is moving upward.
How is the energy transferred from one store to another?
Kinetic store of popper toy is depleted
Gravitational store of popper is filled
Energy is transferred mechanically via the force of gravity
What are the disadvantages of a hydroelectric power station?
- flooding of valleys and loss of habitats
- flooding of valleys and displacement of communities
- expensive to build
Using the Sankey diagram calculate the efficiency of the electric motor and the percentage the energy wasted.
eff = useful energy out / total energy in
36J/50J = (72/100) x 100 = 72%
22% of energy is wasted as thermal store of the surroundings
What are the advantages of nuclear power?
- does not produce carbon dioxide- a greenhouse gas
- does not use fossil fuels
- reliable continuous supply of electricity
What energy store is depleted and which energy store is filled when the popper toy is release.
How is this energy transferred from one store to another?
Elastic store of popper toy is depleted
Kinetic store of popper toy is filled
This energy is transferred mechanically via a spring force
What energy store is being depleted in the Sun? How it energy transferred or shifted from the Sun?
Nuclear store is being depleted (emptied)
Energy is shifted or transferred away from the sun by radiation (infrared, visible light UV etc…)
Thermal energy is transferred from a hot Leslie cube in three ways.
Which side will radiate the most heat?
Which side will radiate the least heat?
The matt black side will radiate the most heat
The shiny silvery side will radiate the least heat
How is Sankey diagram constructed?
- using graph paper
- create a scale- e.g. one small square = 10J
If Total Energy In is= 200J arrow should be 20 squares in width to start.
Useful Energy Out - straight arrow forward
5 squares = 50J
-Wasted Energy Out -arrow curling downward
15 squares = 150J
What are the advantages of tidal power?
- renewable
- no polluting gases produced
- reliable- we know when the tides occur
- saves fossil fuels
What are the advantages of wave power?
- renewable
- does not produce harmful gases
- a free energy source
- does not use fossil fuels
-
What are the disadvantages of wave power?
- not reliable- no waves, no energy
- can only be built for countries with coastal regions
- a danger to boats/ships
- you need a large number to replace one power station
Using ideas on convection describe how heat is transferred in a room.
- air above the radiator is heated
- hot air expands and becomes less dense
- hot air rises and moves along the ceiling
- hot air cools (becomes denser) and falls
- cool air is pulled towards radiator to replace hot air which moved upward
How is the chemical store of biomass usefully transferred?
Chemical store of biomass is transferred via heating when biomass if burnt
This is mechanically transferred to a turbine which is mechanically transferred to a generator
The kinetic store of the generator turning is transferred electrically to the wires.
What are the disadvantages of solar power (solar cells)?
- they are expensive
- they are inefficient
- they are not reliable- less sun, less power
What are the disadvantages of geothermal power
- can only be built where the Earth’s crust is thin- limited places
- high initial set-up costs
- very high temperatures needed to produce power- need to produce steam, not just hot water.
What energy store is being depleted in a nuclear power station?
How is this energy usefully transferred to the nearby town?
Nuclear store of the uranium is being depleted.
The energy is transferred electrically to the nearby town.
Nuclear energy is being depleted in a nuclear power station
How is this energy wastefully transferred?
heating from the reactor, turbines, generator and wires
radiation of sound from turbines and generators.
What are the advantages of solar power (solar cells)?
- does not use fossil fuels
- renewable
- does not produce carbon dioxide or other pollutants
What energy store is being filled as this hot cup of tea cools?
Thermal store of surroundings (air, table etc)
What is conduction?
Conduction occurs when heat is transferred through a material from particle to particle
Energy is stored chemically in the match.
How is energy transferred or shifted from the match?
Which energy store is being filled?
Chemical store the match is emptied.
This energy is shifted/transferred away from the match by radiation (light) and heating to the surroundings.
The thermal store of the surrounding is being filled
State the different ways in which heat is transferred from a thermos flask.
What energy store is depleted and which energy store is filled as water rushes down the tunnels from a hydroelectric dam to the turbines below?
Gravitational store of the water is depleted and kinetic store of water is filled.
Which cup will radiate the most heat?
The cup at 80°C will radiate the most heat to the surroundings.
The greater the temperature difference the greater the rate of heat transfer.
Explain why heat is transfer is reduced in the following ways.
Lid- reduces convection
Vacuum- reduces conduction
Shiny surface- reduces radiation
Lid stops heat loss by convection- lid traps air and does not allow it to move, no convection currents created which carries heat energy away
Vacuum stops heat loss by conduction- no particles means heat cannot be transferred from particle to particle through the walls to the outside
Shiny surface stops heat loss by radiation as shiny silvery surfaces reflect heat radiation back into the flask.
Which energy store is being filled as the blades accelerate and how is energy usefully shifted/transferred from the wind turbine
Kinetic store of the blades are filled
Their energy is usefully transferred mechanically to the kinetic store of the generator
Energy is usefully shifted/transferred from the generator electrically
What are the advantages of geothermal power?
- it is renewable
- once set-up it is free
- does not produce pollutants- no harmful gases produced
What is a solar furnace?
A solar furnace consists of a large number of mirrors which reflects the sun’s radiation to one point.
At this focal point is a pipe with water. The radiative energy (light) heats the water and creates steam.
Steam turns a turbine, which turns a generator producing electricity.
What are the disadvantages of tidal power?
- You need an estuary- limited places to build
- it disrupts the movement of boats/fish etc..
- not constant power, times of day where less power is given out
How does the heatproof mat reduce heat loss?
The heatproof mat is an insulator
It reduces heat loss by conduction to the table below
Conduction occurs when heat is transferred from particle to particle when objects are in contact.
How does the heatproof mat reduce heat loss?
The heatproof mat is an insulator
It reduces heat loss by conduction to the table below
Conduction occurs when heat is transferred from particle to particle when objects are in contact.
