Energy Flashcards
What are the 8 energy stores
Thermal
Kinetic
Gravitational potential
Elastic potential
Chemical
Magnetic
Electrostatic
Nuclear
What is a closed system
Where neither matter nor energy can enter or leave
What are the 4 ways energy can be transferred
Electrically
Heating
Radiation
Mechanically
What is specific heat capacity
Specific heat capacity is the amount of energy needed to raise the temperature of 1kg of a substance by 1C
What is the equation for specific heat capacity
E=m x c x change in temperature
What is the conservation of energy principle
Energy can be transferred usefully, stored or dissipated, but can never be created or destroyed
What is the equation for power
P = E/t
P = W/t
Which state does conduction happen mainly in
Solids
What is conduction
Conduction is the process where vibrating particles transfer energy to neighbouring particles
How does conduction happen
- Energy is transferred by heating to the thermal stores of the object
- This is then shared across the kinetic energy stores of the particles
- This continues throughout the object until the energy is transferred onto the other side of the object
- It is then usually transferred until the surroundings
What is thermal conductivity a measure of
A measure of how quickly energy is transferred through a material through conduction
What is convection
Where energetic particles move away from hotter to cooler regions
What states of matter can convection occur in
Liquids and gases
How does convection happen
- Energy is transferred by heating to the thermal store of the liquid or gas
- Unlike in solids, the particles in liquids and gases can move. So, when heated, the particles will move faster and the space between individual particles increases
- Because liquids and gases can flow , the warmer and less dense region with rise above the cooler, more dense regions, creating a convection current
How to reduce unwanted energy transfers
Lubrication reduces frictional forces
Insulation reduces the rate of energy transfer by heating
What is the equation for efficiency
Efficiency = Useful output energy transfer/ Total input energy transfer
Efficiency = Useful power output/ Total power input
Examples of non-renewable energy sources
Coal
Oil
Natural gas
Sources of renewable energy
Solar
Wind
Water waves
Hydro-electricity
Biomass
Tides
Geothermal
How can renewable energy sources be used for heating
Geothermal heat pumps
Solar water heater
Burning bio-fuel
What is bio-fuel made from
Made from plant products or animal dung
Pros and cons of biofuel
Pros:
Supposedly carbon neutral
Fairly reliable as crops only take a short amount of time to grow
Cons:
Cost of refinery is high
Some areas have been cleared to make room to grow biofuels
Disadvantages to renewables
Highly expensive
Less reliable
Research required
