Energy Flashcards
what is the law of conservation of energy
energy cannot be created or destroyed but it can be transfered from one form into another
energy transfer of lighting a match
kinetic energy + chemical energy –> heat energy –> light energy
energy transfer in a circuit where a bulb lights
electrical –> heat –> light
energy transfer of a falling pen
gravitational potential energy –> knetic energy
energy transfer of a sound generator
electrical –> kinetic energy –> sound
what is a electrical transfer
a charge moving through a potential difference
what is a mechanical transfer
an object moving due to a force acting on it
energy transfer of putting 100g on a spring
gravitational potential energy –> elastic + kinetic
energy transfer of an atomic bomb explosion
nuclear –> heat –> gravitational potential energy + light + kinetic + sound
what is a heating transfer
energy transferred from a hotter object to a colder object
what is a radiation transfer
energy transfered by electromagnetic waves
what does efficiency always having a value less than one tell us
that during the energy transfer there is always some “less useful” energy being produces (usually heat and sound)
what does the width of the arrow mean in a sankey diagram
they are in proportion to the amount of energy involved
what does the arrow down mean
less useful energy
what doesn’t matter in a sankey diagram
the length
what does a sankey diagram show
the energy efficency
how does wind energy work
wind turbines use energy from the kinetic energy store of moving air to generate electricity. wind turns the blades which turn as generator inside it
how does solar heating system transfered by energy
solar cells use energy from the sun to directly generate DC electricity
advantages of solar heating system
solar energy is a renewable energy resource and there are no costs
no harmful polluting gases are produces
what are disadvantages of solar heating systems
space is needed for installing solar cells
solar cells do not work at night
how is hydroelectric power generated
it reuqires the flooding of a valley by building a big dam
rainwater is caught and pushed out through turbines
it transfers the GPE stores of the water to the kinetic store as it falls
advantages of hydroelectricity
clean and renewable
valves can be opened quickly to produce energy
no pollution when running
disadvantages of hydroelectricity
objections from people in the surrounding enviroment
affects wildlife by flooding the valley
contruction of dams in expensive
how do geothermal resources work
hot water and steam from deep underground can be used drive turbines
explain how hot rocks generate electricity
the rocks are hot which causes hot water and steam which rises
so deep wells can be drilled down to the hot rocks and cold water pumped down
the water runs through the fracture in the rocks is heated up
it returns to the surface as hot water and steam and the energy is transferred from the thermal energy stores to kinetic energy stores to generate electricity
how does tidal power generate electricity
tidal barrages are big dams build across river mouths with turbines in them
as the tide comes in it fills up the mouth of the ricer to several meters high. the water is then let out through the turbine which drive the turbine to produce electricity
kinetic energy of moving water –> electrical energy
how does wave energy work
the energy is transferred from the kinetic energy store of the waves to the kinetic energy store of the turbine and used to generate electrcity
how do fossil fuels generate electricity
In large power stations they are burned in the presence of oxygen. As the fuel burns the heat energy is used to heat water, as it is heated it produces steam which in turn rises and drives a turbine.
as the turbine moves it generates electricity
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how does nuclear power generate electricity
nuclear fission of uranium produces heat to make steam turn the turbines
what is conduction
The transfer of heat energy through the vibrations of particles in a medium. The particles bump into nearby particles and make them vibrate
what is convection
convection occurs when the more energestic particles move from a hotter region to a cooler region - and transfer energy as they do
what is radiation
Radiation is the transfer of heat energy from a region of high temperature to a region of low temperature by infrared radiation.
what is an experiment for conduction
placing ball bearings onto different metals onto a ring conductor with a little bit of wax
the conduction ring is heated the metal that conducts the best will mean the ball will drop first
what is an experiment for convection
place postassium permanganate crystals in a beaker of water (one hot one cold)
then heat the breaker with a bunsen burner
the hot water creates a faster convection current becuase the high the temperature the high the kinetic energy
what is an experiment for radiation
the color of the flasks are different (black, dull grey, white and silver)
hot water is placed in the flasks and the temperature is recorded
the one that cools the fastest is the poorest emitter
the one that cools the slowest is the best emitter
what is double glazing
windows made with 2 panes of glass seperated by a gap filled with air or an insulating gas
the gap acts as a barrier reducing heat transfer
the insulating properties of double glazing help to keep the interior warm or cold
what is loft insulation
adding a layer of insulating material such as mineral wool, fibreglass or foam boards to the floor of the roof or loft space
heat rises so it traps the heat
what is a mylar blanket
they are known as emergency blankets
the reflectice material helps to trap a persons body heat and reflect it bac twoards them
how does a thick wooly jumper work
a wooly jumper is made from wool fibres which provides insulation
wool has tiny air pockets which retain heat and also absorb moisture without feeling damp and helping to regulate body temperature
what is work
whenever an energy transfer takes place
what is power
power is the rate at which energy is transferred
what is weight
the force of gravity which pulls an object down to the ground
what is kinetic energy
objects which are moving have kinetic energy
it depends n the mass and speed of an object
what is gravitational potential energy
when an object is raised above the ground it gains GPE
the amount gained depends of the mass of the object and the strength of the gravitation field
what are energy transfers
the relocation of energy from one place to another, usually in a different form
describe the energy transfers of a bat hitting a ball
some energy is usefully transferred mechanically from the kinetic energy store of the bat to the kinetic energy store of the ball. the rest is wasted
describe the energy transfer of a bunsen burner and beaker
energy is usefully transferred by heating from the chemical energy store of the gas to the thermal energy stores of the beaker and the water.
energy is also wastefully transferred by heating to the thermal energy stores of the stand and surroudnings
explain how objects emmit and absorb relating to their surface area and temperature
all object are continually emitting and absorbing
black + dull = best aborbers and emitters
white + shiny = best relfectors
shiny = reduce unwanted energy transfers
the higher the temperature and the greater the surface area the more radiation is emitted
work done =
energy transfered
advantages of fossil fuels
Reliable. Can produce large amounts of energy consistently. Can respond to changes in demand.
disadvantages of fossil fuels
Produces carbon dioxide (CO2) which contribute to global warming
sulphur dioxide which causes acid rain
advantages of nuclear power
Reliable
Produces large amounts of energy consistently Produces no pollution or CO2
Large amounts of energy are produced from small amounts of fuel.
disadvantages of nuclear power
Produces radioactive waste that takes thousands of years to decay and must be safely disposed of. Nuclear power stations are expensive to build and maintain, and take many years to build. Can not be turned on and off quickly so cannot respond to changes in demand.
advantages of wind power
Produces no pollution or CO2
Are cheap to build and maintain
disadvantages of wind power
Non-reliable. Only generate electricity when the wind is blowing in a certain direction. Some people consider them visual pollution (they spoil the view)
advantages of hydroelectric power
Reliable. Can respond to meet changes in demand. No pollution or CO2 produced (unless a pump is used to return the water as this uses fossil fuels).
disadvantages of hydroelectric
Can involve flooding large areas to build reservoirs which destroys habitats and displaces wildlife
disadvantages of geothermal power
Not many suitable locations. Can release methane (a greenhouse gas) in the extraction process.
advantages of geothermal power
Reliable
