P1 - Energy Flashcards
What are the four ways energy can be transferred
Mechanically
Electrically
By heating
By radiation
Kinetic energy store
Anything moving has kinetic energy store
Thermal energy store
All objects have energy in this store.The hotter the object, the more energy in this store
Chemical energy store
Anything that can release energy by a chemical reaction has energy in this store,
Gravitational potenial store
Any object raised above ground level has energy in this store
Elastic potential energy store
Anything stretched has energy in this store, like springs or rubber bands
Electrostatic energy store
Two charges that attract or repel each other have energy in this store
Magnetic energy store
Two magnets that attract or repel each other have energy in this store
Nuclear energy store
The nucleus of an atom releases energy from this store in nuckear reactions
What is the conservation of energy principle ?
Energy can be transferred usefully , stored and dissipated but can never be created or destroyed
Whenever a system changes
All the energy is simply moved between stores.Energy never disappears
What does energy dissipated ?
It’s wasted energy
Forces cause mechanical energy transfers
If a force moves an object then work is done.Work done is the same as energy transferred.So energy transferred mechanically when a force moves an object.
What is power
Power is the rate of energy transfers .How much work is done per second
When energy is transferred between stores , some energy is transferred to the store you want t in.However
In any transfer , some energy is always dissipitated
These useless energy stores are usually
Thermal energy stores
Friction acts between all objects that rub together.This causes energy to
Be dissipated
What can reduce friction between objects
Lubrication
What is thermal conductivity
A measure of how quickly energy is transferred by conduction through a material
Materials with a high thermal conductivity
Transfers lots of energy in a short time
Materials with a low thermal conductivity are called
Thermal insulators
What do thermal insulators do
They reduce unwanted transfers by heating
Energy is also wasted when energy is transferred.The less energy wasted the
More effient the energy transfer is
The efficiency of an energy store is a measure of
The amount of energy that ends up in useful energy stores
Equation for efficiency of any energy transfer
Energy = useful output energy transfer over total input energy transfer
What are non renewable resources
Resources that will run out one day such as fossil fuels and nuclear fuel
What are renewable resources
Renewable resources can be replenished ( replaced ) as quickly as they are being used .
Energy resources can be used for transport
Non renewable resources such as petrol or diesel are used in most vehicles.
Coal used in steam trains to boil water to produce steam
How can renewable energy resources be used for transport ?
Vehicles can run on bio fuels or a mix of bio fuels and diesel
Energy resources can be used for heating
Natural gas is burnt to heat water in a boiler.Hot water is then pumped to radiators
Hw can renewable energy resources be used for heating
Biofuel boilers work in the same way as normal boilers
How is wind power generated
Wind turbines usually put out in open space
When the wind turbine turns the blades , electricity is produced
They produce no pollution
Do not cause damage ro the environment .
Not as reliable as other energy resources
Turbines stopped if wind is too strong
Solar panels
Dolar panels generate electricity directly from the sunlight
They create no pollution
Solar power energy omly generates through the day.
Geothermal power
Geothermal power uses energy from the thermal energy stores of hot rocks below the Earth’s surface.Can be used to generate electricity or to heat buildings.
Very reliable as the hot rocks are always hot
Small impact on the environment
Hydro electric power
Hydro electric power uses falling water.Hydro electric power usually involves building a big dam across a valley.Valley is usually flooded .Water is allowed tomflow out through turbines which generates electricity.Nompollution
Big impact on environment as valley floods.Plants rot and release greenhouse gases , animals and plants lose their habitats
Wave power
Turbines around the coast are turned by water waves and electricity is generated .Nompollution.
Disturb seabed and the habitats of animals .Unreliable as waves drop when the wind does
What are biofuels
Biofuels are fuels created from plant products or animal dung .They can be burnt to produce electricity
