4 ENERGY Flashcards
Unit for mass
Kilogram (kg)
Unit for energy
Joule (J)
Unit for distance
Metre (m)
Unit for speed
Metre/Second (m/s)
Unit for acceleration
Metre/Second^2 (m/s^2)
Unit for force
Newton (N)
Unit for time
Second (t)
Unit for power
Watt (W)
Name the energy stores
- Chemical
- Kinetic
- Thermal
- Magnetic
- Gravitational
- Elastic
- Electrostatic
- Nucleur
Name the energy transfers
- Mechanically
- Electrically
- by heating
- by radiation (light + sound)
State the principle of the conversation of energy
Energy cannot be created or destroyed, only transferred from one store to another
Effeciency equation
Efficency = Useful energy output / Total energy input
How do you get energy effeciency as a percentage
Multiply by 100
Unit for effeciency
No unit
How to draw a sankey diagram
- Label everything with input/output, store and effeciency
- Width of arrows represent effeciency
Describe the process of conduction
- Heated particles vibrate
- Pass energy to neigbhouring particles via collisions
- Energy passes throughout material, so matter must be in contact for particles to collide (solid)
Why are metals good conductors of heat
Free electrons for more collisions
Why are solids good conductors
Particles are close togetherm and have strong forces between them
Why are insulators bad at heat transfer (conduction)
They have no free electrons, so there are less collisions
Why are liquids and gases bad at transferring heat by conduction
Particles are far apart, so collisons transferring energy are more difficult / less succsesful
Describe how to carry out a conduction experiment
- Attach a metal rod to clap stand with a bunsen burner at the other end
- Attach paperclip at equal distance (ruler) along rod, with vasaline
- Whit stopwatch, record time taken for each paperclip to fall
- Repeat for rods of different materials
Describe how convection works
- Hot object heats the air above it
- Particles in air vibrate more
- Particles in air spread out, and become less dense
- Less dense air rises
- As hot air cools, it falls and the denser coled air replaces the hot air
- Sets up a convection current
What states does convetion occur in
Solids and Liquids
State ways to reduce convection currents
- Foam
- Lid
- Vaccum
THEY ALL TRAP AIR
State how to observe a convection current forming
Place a dye into the corner of a large trough of water and only heat that side and observe the pattern
How does radiation (heat transfer) travel, and why is that special
Travels as EM waves - Can travel through a vaccum
What is the link between surfaces when radiating and absorbing heat
Matt and black materials are good, whereas shiny and white/silver materials are bad
How does the rate of cooling differ when compared with room temperature
- Rate of cooling is greater when object is hotter
- Larger difference betwen water, and room temperature
- On a graph, an original steep gradient would level out (more energy transferred more rapidly)
Describe different experiments to investigate radiation
- Place silver and black tin on mat, and fill with boiling water
- Record initial temperature, and record in stages with thermometer
OR
Use a leslie cube (metal) with 4 different surfaces, using an infrared ray to observe temperatures
How does loft insulation minimise heat loss
- Fibreglass is an insulator with pockets of air
- Air is poor conductor, as trapped air cannot move
- Prevents convection current being set up
State the 3 ways that heat loss can be minimised in a home
- Loft insulation
- Double glazing
- Shiny foil behind radiators
Hoe does double glazing prevent heat loss
- Vaccum between panes of glass so no particles can transfer heat by collisions (no conduction)
- No convection currents can form
How does shiny foil behind radiators reduce heat loss
- Foil is silvery in colour, and shiny in texture
- Prevents heat loss by radiation
- Heat radiating from radiator, is refelcted back into room
How does shiny foil behind radiators reduce heat loss
- Foil is silvery in colour, and shiny in texture
- Prevents heat loss by radiation
- Heat radiating from radiator, is refelcted back into room
Describe the energy transfer at a fossil fuel power station
- Chemical store of fuel
- Thermal store of water
- Kinetic store of water
- Mechanical transfer via force of steam on turbine blaes
- Kinetic store of turbine
- Mechanical transfer to generator
- Kinetic store of generator
- Electrical transfter from generator via wires
Advantages of fossil fuel power stations
- Reliable
- Constant source of power
- Burning fossil fuels releases a lot of energy relatively cheaply
- Plenty of fossil fuel power stationa already
Disadantages of fossil fuel power stations
- Non-renewable
- Produces CO2 (Greenhouse gas)
- Produces SO2 and Nox (acid rain)
Energy transfer at nucleur power station
- Nucleur store of uranium
- Thermal store of water
- Kinetic store of water
- Mechanical transfer via force of steam on turbine blades
- Kinetic store of turbine
- Mechanical transfer to generator
- Kinetic of generator
- Electrical transfer from generator via wires
Advantages to nucluer power station
- Reliable
- Constant source of power
- No Co2 (greenhouse gas)
- No So2 or Nox (acid rain)
- Small amount of fuel creates lots of energy
Disadvantages to nucluer power station
- Non-renewable
- Produces radioactive waste that takes thousands of years to drop to a safe level
- Possibility of major meltdown which have catastrophic effect on enviroment
- Expensive to build, maintaina nd decommission
Energy transfer at wind power station
- Kinetic store of wind
- Mechanical transfer onto blades via force of wind
- Kinetic store of blades
- Mechanical transfer to generator
- Kinetic store of generator
- Electrical transfer from generator via wires
Advantages to wind power station
- Cheap to run (wind is fun)
- No fossil fuels
- Renewable source
- No Co2 (global warming)
- No So2 or Nox (acid rain)
Disadvantages to wind power station
- Not reliable (need wind)
- Spoil view
- Large number to produce energy
- Danger to birds
- Noisy
- Expensive to set up
Energy transfer of hydroelectric power station
- Graviatational of water behind dam
- Mechanical transfer to water
- Kinetic store of water
- Mechanical transfer on turbine blades
- Kinetic store of turbine
- Mechanical transfer to generator
- Kinetic of generator filed
- Electrical transfer from generator via wires
Advantages of hydroelectric power station
- Cheap (no fuel)
- Immediate response to increase demand of electricity
- Reliable
- No fossil fuels
- Renewable
- No Co2 (greenhouse gas)
- No So2 or Nox (acid rain)
- Provides recreational activites like fishing
Disadvantages of hydroelectric power station
- Initailly expensive to build
- Loss of habitat for organisms living in flooded valley
- Towns relocated
- Fish spawning routes distrupted
- Only in mountainous reigons
Energy transfers of geothermal power station
- Thermal and nucleur store of earths core
- Transfered by heating to water
- Thermal store of water
- Kinetic store of water
- Mechanical transfer to turbine blades by force of steam
- Kinetic store of turbine
- Transfer mechanically to generator
- Kinetic store of generator
- Transfer electrically from generator via wires
Advantages to geothermal power station
- Cheap to run (no fuel)
- Reliable
- Constant source of power
- No fossil fuels
- Renewable
- No Co2 (greenhouse gas)
- No So2 or Nox (acid rain)
Disadvantages to geothermal power station
- Initially expensive to drill
- Few places where can be set up - thin crust
Energy transfer of solar heating system
- Nucleur store of sun
- Transfered as light radiation
- Furnace absorbs light radiation
- Thermal store of water
- Kinetic store of water
- Mechanical transfer to turbine by force of steam on blades
- Kinetic store of turbine
- Mechanical transfer to generator
- Kinetic of generator
- Electrical transfer by wires from generator
Advantages of solar heating system
- Cheap to run (no fuel)
- No fossil fuels
- Renewable
- No Co2 (greenhouse gas)
- No so2 or nox (Acid rain)
Disadvantages to solar heating system
- Initially expensive to build
- Not reliable (need good weather)
Disadvantages to solar heating system
- Initially expensive to build
- Not reliable (need good weather)
Energy transfer in solar cell
- Nucleur store of sun
- Light radiation transfer
- Solar cell absorb light radiation
- Rlectrical transfer via solar cell wires
Advantages to solar cells
- Cheap (no fuel)
- No fossil fuels
- Renewable
- No Co2 (fossil fuels)
- No so2 or nox (acid rain)
Disadvantages to solar cells
- Initailly expensive to build
- Not reliable (need good weather)
- Need lots for same ammount of energy
- Unsightly
Equation for work done
Work done = force x distance moved in direction of the force
Work done symbol equation
W = Fd
What is work done equal to
Energy transferred
What is energy transferred equal to
Work done
Equation linking work done and energy transferred
Work done = energy transferred
Unit for work done
Joules (J)
Define power
The rate of transferring energy or the rate of doing work
Power equation (energy transferred)
Power = Energy transferred / time taken
Power equation (energy transferred) - SYMBOL
P = E/t
Power equation (work done)
Power = work done / time taken
Power equation (work done) - SYMBOL
P = W/t
Equation for energy transferred (work done)
Power x Time
Unit for GPE and KE
Joules (J)
Equation for gravitational potential energy
Gravitational potential energy = mass x gravitational field strength x height
Equation for gravitational potential energy - SYMBOL
GPE = mgh
Equation for kinetic energy
Kinetic energy = 1/2 x mass x speed ^2
Equation for kinetic energy - SYMBOL
KE = 1/2mv^2
What links GPE and KE
GPE lost = KE gained
How does GPE link work done
- GPE = KE
- mgh = 1/2mv^2
- mg = w (force)
- GPE = force x height
- mgh = work done
Advantages of hydroelectric power station
- Cheap (no fuel)
- Immediate response to increase demand of electricity
- Reliable
- No fossil fuels
- Renewable
- No Co2 (greenhouse gas)
- No So2 or Nox (acid rain)
- Provides recreational activites like fishing
Energy transfer at wind power station
- Kinetic store of wind
- Mechanical transfer onto blades via force of wind
- Kinetic store of blades
- Mechanical transfer to generator
- Kinetic store of generator
- Electrical transfer from generator via wires
Advantages of fossil fuel power stations
- Reliable
- Constant source of power
- Burning fossil fuels releases a lot of energy relatively cheaply
- Plenty of fossil fuel power stationa already
State how to observe a convection current forming
Place a dye into the corner of a large trough of water and only heat that side and observe the pattern
