P1,2&3 energy Flashcards
what is a system
an object or group of objects
what happens when a system changes
there are changes in the way that energy is stored
what is internal energy
the total kinetic and potential energy
what is the conservation of energy
energy cannot be created or destroyed
how do you reduce unwanted energy transfers
lubrication
thermal insulation
what is meant by thermal conductivity
how well a material conducts energy when heated
what are the two walls of a house called
external brick wall
internal breezeblock wall
what keeps houses warm
insulating material which a a very low thermal conductivity and reduces overall thermal conductivity of the wall by over 10x
why do houses have double glazed windows
they have a very low thermal conductivity so less heat escapes
what is loft insulation
a material with a low thermal conductivity so less thermal energy passes through
what is the equation for power
power = energy / time
why can no device be more than 100% efficient
you cant get more energy than you put in
how would you investigate the heat capacity of materials
measure start temperature
switch on electric heater
measure end temperature
measure voltage and current to find power
repeat using different liquids
calculate specific heat capacity
what is the specific heat capacity
the amount of energy required to raise the temperature of one kilogram of the substance by 1 degree Celsius
what are earths main energy resources
fossil fuels (coal, oil and gas),
nuclear fuel,
bio-fuel,
wind,
hydroelectricity,
geothermal, the tides,
the Sun and water waves
what is a renewable energy source
an energy source which can be replenished
what is a non renewable energy source
energy sources which will eventually run out
what are the uses of energy resources
heating
transport
electricity generation
what happens in a closed system
total energy never changes but it can be transferred from one store to another
what are the energy transfers when an object is projected upwards
kinetic energy to gravitational potential
what are the energy transfers when an object hits an obstacle
kinetic energy to thermal and sound energy
what are the energy transfers when a car is accelerating
chemical to kinetic
what are the energy transfers when a car brakes
kinetic to thermal
what are the energy transfers when water boils in a kettle
electrical to thermal
what are the main uses of biofuel
transport and electricity generation
what are the disadvantages of biofuel
large areas of land are needed can be at the expense of crops in poorer countries
what are the advantages of biofuel
it is a renewable energy source
what are the main uses of wind
electricity generation
what are the disadvantages of wind turbines
not a constant source of energy
noisy
some people think they ruin the countryside
hat are the advantages of wind turbines
its a renewable energy source
what are the main uses of hydro electricity
electricity generation
what are the advantages of hydroelectricity
renewable
what are the disadvantages of hydroelectricity
large areas of land must be flooded
alters ecosystems
displaces people living there
what are the main uses of geothermal
heating
electricity generation
what are the advantages of geothermal
renewable
what are the disadvantages of geothermal
only available in a limited number of places
what are the main uses of tidal
electricity generation
what are the advantages of tidal
renewable
what are the disadvantages of tidal
can alter habitats variation in tide can affect output
what are the main uses of solar
electricity generation
heating
what are the advantages of solar
renewable
what are the disadvantages of solar
depends on light intensity
expensive
what are the main uses of water waves
electricty generation
what are the advantages of water waves
renewable
what are the disadvantages of wtaer waves
unreliable
alter habitats
what are the main uses of nuclear fuel
electricity generation and military support
what are the disadvantages of nuclear fuel
produces radioactive waste
costly to build
non renewable
what are the advantages of nuclear fuel
reliable
what are the main uses of coal
heating transport
electricty
what are the advantages of coal
reliable
what are the disadvantages of coal
greenhouse gases
acid rain
what are the main uses of oil
transport
heating
what are the advantage sof oil
reliable
provides compact source of energy for transport
hat are the disadvantages of oil
environmental damage
what are the main uses of gas
heating
electricity
transport
hat are the advantages of gas
reliable
what are the disadvantages of gas
produces carbon dioxide
