Energy Transfers and Resources

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Created by
Ada Kwok

Cards (31)

  • Stores of energy
    • Kinetic
    • Gravitational
    • Chemical
    • Elastic
    • Magnetic
    • Electrostatic
    • Nuclear
    • Thermal
  • Energy transfers

    Mechanical - When a force acts on a body
    Electrical - Electricity transferring energy from a power source to a component within a circuit
    Heating - Conduction, convection, and radiation
    Radiation - Light and sound carry energy from one point to another
  • Work done = energy transferred
  • Torch

    Chemical store of battery is depleted.
    Energy is transferred electrically through wires.
    As a result, the filaments thermal store is filled- filament heats up.
    Energy is transferred from the filament to the surroundings by heating and radiation (light)
  • Blender

    Energy is transferred from the mains to the blender electrically through the wires
    Kinetic store of blender blades is filled along with thermal store of motor and blades.
    Energy is transferred from the blender to the surrounding liquid mechanically (a force) and via heating and radiation (sound)
  • Catapult (released)

    Elastic store of rubber bands is depleted
    Energy is transferred mechanically to the kinetic store of rock via an elastic force
  • Microphone

    Energy is transferred to the microphone by radiation (sound)
    Energy is transferred from the microphone electrically through wires
  • Conservation of energy

    Energy cannot be created or destroyed, only transferred from one store to another.
  • Efficiency = useful energy output/total energy output
  • A sankey diagram gives a visual illustration of an input/output situation. It is drawn to scale.
  • Thermal energy is transferred from a hotter area to a colder one.
    • Conduction occurs (mainly) in solids
    • Convection occurs in fluids (liquid and gas)
    • (Infrared) radiation, and electromagnetic wave that can travel through solids, liquids, gasses, and vacuums.
  • Conduction

    Conduction occurs mainly in solids.
    When an object is heated, particles begin to vibrate.
    When particles vibrate, they collide into other particles, passing on energy.
    Metals are good conductors because they feature free electrons.
    Solids are good conductors because particles are close together.
    Good insulators are poor conductors.
    Air is a good insulator because air is a gas and particles are far apart.
    Conduction cannot occur in a vacuum because there are no particles.
  • Convection

    Convection occurs in fluids (liquids and gases).
    1. Fluid is heated, molecules are pushed apart (thermal expansion).
    2. Hot fluid becomes less dense.
    3. Less dense fluid rises, cooled fluid sinks to replace it.
    4. Hot fluid cools, contracts, and sinks.
    5. This phenomenon is called a convection current.
  • Some examples of everyday phenomena of convections are
    • gliders or birds in thermals
    • boiling water in a pot or hot water systems
    • The hot objects heats the air above it
    • The particles in the air vibrate more
    • This makes the air particles spread out and become less dense
    • The less dense air rises
    • As the hot air cools it falls and the denser cool air replaces the hot air which sets up a convection current.
  • To investigate convection:
    • Independent: Container with lid, container without lid
    • Dependent: Temperature drop after 20 minutes
    • Control: Volume of water, initial temperature of water, room temperature, same type/shape of container, same initial temperature of container
    • The container with the lowest temperature drop loses the least amount of heat via convection
  • Infrared (IR) radiation is an EM wave that transfers heat, and thus behaves like light; it can be emitted, absorbed or reflected.
  • Light, shiny surface: Good reflector, bad absorber, bad emitter
    Dark, matt surface: Bad reflector, good absorber, good emitter
  • Use thermal insulation
    • The lower the thermal conductivity (doesn't transfer heat very well), the more heat is insulated
    • The thicker the material, the more heat is insulated
    • Insulators trap pockets of air, reducing the movement of fluid
  • Loft insulation: Reduces heat loss by conduction and convection. It is made of glass which is an insulator and has air pockets; air is a poor conductor also. The pockets of air prevents convection currents being set up.
  • Double glazing: Reduces heat loss by conduction and convection. The vacuum between the panes of glass means that there are no particles to transfer the heat via collisions/conduction or convection currents.
  • Shiny foil behind radiators: Foil is silvery in colour and shiny in texture. This reduces heat loss by radiation. The heat radiating from the radiator is reflected back into the room.
  • Coal, oil and gas
    Energy Transfers
    • Chemical store of fuel is depleted
    • Thermal store of water is filled, boiling the water
    • Kinetic store of steam is filled
    • Mechanical work is done on the turbine due to the force of the steam
    • Increase in the kinetic store of turbine
    • Mechanical work is done on the generator by the turbine
    • Increase in the kinetic store of generator
    • Electrical work is done on the electrical grid
  • Coal, oil and gas
    Advantages
    • Energy generation can change to meet demand
    • Reliable
    • Does not depend on weather
    Disadvantages
    • Non-renewable
    • Produces carbon dioxide which is a greenhouse gas
    • Produces sulphur dioxide and nitrous oxides which create acid rain
  • Nuclear
    Energy Transfers
    • Nuclear store of uranium is depleted
    • Thermal store of water is filled, boiling the water.
    • Kinetic store of water is filled, boiling the water
    • Kinetic store of steam is filled
    • Mechanical work is done on the turbine due to the force of the steam
    • Increase in the kinetic store of turbine
    • Mechanical work is done on the generator by the turbine
    • Increase in the kinetic store of generator
    • Electrical work is done on the electrical grid
  • Wind
    Energy Transfers
    • Kinetic store of wind is depleted
    • Mechanical work is done on the turbine due to the force of the wind
    • Increase in the kinetic store of turbine
    • Mechanical work is done on the generator by the turbine.
    • Increase in the kinetic store of generator
    • Electrical work is done on the electrical grid
    Advantages:
    • Renewable
    • Produces no polluting gasses
    Disadvantages:
    • Noise pollution
    • Visual pollution
    • Weather dependent (windy)
    • Dilute source of energy
    • Energy generation cannot change to meet demand
  • Hydroelectric

    Energy Transfers
    • Gravitational store of water is depleted
    • Mechanical work is done on the turbine due to the force of the water
    • Increase in the kinetic store of turbine
    • Mechanical work is done on the generator by the turbine
    • Increase in the kinetic store of generator
    • Electrical work is done on the electrical grid
    Advantages
    • Renewable
    • Produces no polluting gasses
    • Always available
    • Energy generation can change to meet demand
    • Not weather dependent
    Disadvantages
    • Requires large dam/flooding large area
    • Geographical limitations (flowing water, hills/mountains)
  • Wave

    Energy Transfers
    • Kinetic and gravitational stores of water waves are alternately depleted
    • Mechanical work is done on the generator due to the force of the water
    • Increase in the kinetic store of generator
    • Electrical work is done on the electrical grid
    Advantages
    • Renewable
    • Produces no polluting gasses
    Disadvantages
    • Weather dependent (waves might not be big enough)
    • May cause harm to wildlife
    • Possible storm damage to generator
  • Tidal
    Energy Transfers
    • Gravitational store of water is deleted
    • Mechanical work is done on the turbine due to the force of the water
    • Increase in the kinetic store of turbine
    • Mechanical work is done on the generator by the turbine
    • Increase in the kinetic store of generator
    • Electrical work is done on the electrical grid
    Advantages
    • Renewable
    • Produces no polluting gasses
    • Reliable, because there are always two tides every day
    Disadvantages
    • The dam may cause local flooding
    • Energy generation cannot change to meet demand
    • Dilute source of energy
  • Geothermal
    Energy Transfers
    • Chemical store of earth's core is depleted
    • Thermal store of water is filled, boiling the water
    • Kinetic store of steam is filled
    • Mechanical work is done on the generator by the turbine
    • Increase in the kinetic store of generator
    • Electrical work is done on the electrical grid
    Advantages
    • Renewable
    • Produces no polluting gasses
    • Doesn't damage the environment
    Disadvantages
    • Depends on geographical location (very few places in the world where you can do this)
    • Very difficult to drill deep into the ground
  • Solar cells
    Energy Transfers
    • Nuclear store of sun is depleted
    • Energy is transferred from the sun as radiation (light)
    • Solar cell absorbs light radiation
    • Energy is transferred electrically via the solar cell wires
    Advantages:
    • Renewable
    • Produces no polluting gasses
    Disadvantages:
    • Weather dependent
    • Does not work at night (no sun)
    • Requires large open spaces
    • Depends on geographical location