Energy Flashcards
What are the units for energy
Joules (J)
What happens to used energy?
It is dissipated
What are the 8 different energy stores?
- Magnetic energy
- Electrostatic energy
- Nuclear energy
- Thermal energy
- Elastic potential energy
- Chemical energy
- Kinetic energy
- Gravitational potential energy
Name some examples of magnetic energy stores
- Magnets
- Compasses
- Maglev trains
Name some examples of thermal energy stores
- Human bodies
- Hot coffee
- Ice particles (vibrate slower but still have energy)
Name some examples of chemical energy stores
- Food
- Muscles
- Electrical cells (eg. in batteries)
Name some examples of kinetic energy stores
- Cars
- Comets
- Planets (orbiting)
Name some examples of electrostatic energy stores
- Electricity
- Thunderclouds
Name some examples of elastic potential energy stores
- Elastic bands
- Compressed springs
- Inflated balloons
Name some examples of GPE energy stores
- Planes
- Hot air balloons
- Jumping
Name some examples of nuclear energy stores
- Nuclear bombs
- Stars
What are the 4 different types of energy transfer?
- Mechanical work
- Electrical work
- Heating
- Radiation
What is mechanical work?
Energy transfer by a force moving an object through a distance
What is electrical work?
Energy transfer through an electrical current
What is heating (energy transfer)?
Energy transfer due to a temperature difference
What is radiation (energy transfer)?
Energy transferred as a wave
Energy cannot be _______ or _________
Created or destroyed
What is internal energy?
The total kinetic energy and potential energy of the particles in an object
What is the equation for GPE?
Give units.
GPE (J) = mass (kg) x gravitational field strength (N/kg) x height (m)
What is the equation for kinetic energy?
Give units.
KE (J) = 1/2 x mass (kg) x velocity2 (m/s)
What can be used to reduce friction between two moving things?
A lubricant
What is the equation for efficiency?
. Useful energy/power out
Efficiency = ————————————
Total energy/power in
What are the 3 different processes of which heat can be transferred?
- Conduction
- Convection
- Radiation
Heat always moved from ___ areas to ____ areas
Hot areas to cold areas
What is conduction?
When thermal energy is transferred through solids, through vibrations
What is convection?
When heat is transferred through either a liquid or a gas
What is this an example of?
Conduction, convection or radiation
The handle of a metal pan getting hot
Conduction
What is this an example of?
Conduction, convection or radiation
An oven cooking a turkey
Convection
What is this an example of?
Conduction, convection or radiation
A toaster making toast
Radiation
What is this an example of?
Conduction, convection or radiation
A metal at room temperature feels cold to touch
Conduction
What is this an example of?
Conduction, convection or radiation
Boiling a kettle
Convection
What is this an example of?
Conduction, convection or radiation
A white shirt keeps you cool in the summer
Radiation
When insulating something, is it better to have a high or a low thermal conductivity?
Low thermal conductivity
What is thermal conductivity?
A measure of how well a material conducts energy when it is heated
Name 4 methods you could use to prevent heat loss in a house
- Double glazed windows
- Underfloor heating
- Loft insulation
- Thicker walls
How does double glazing help prevent heat loss?
Trapped air between the glass is a good insulator which therefore reduces heat loss
How does underfloor heating help to prevent heat loss?
Heat comes from the floor, so heat isn’t able to escape through there
How does loft insulation help prevent heat loss?
Trapped air is a good insulator which will therefore reduce heat loss
Name 2 ways to reduce unwanted energy transfers
- Lubrication
- Thermal insulation
How does increasing a wall’s thickness reduce heat loss?
The energy must travel further before it is transferred to the outside
Name some renewable energy sources
- Solar
- Wind
- Hydroelectric
- Geothermal
- Bio-fuel
- Tidal
Name the 2 non renewable sources of energy
- Fossil fuels
- Nuclear
Name 3 different types of fossil fuels
- Oil
- Coal
- Natural gas
What are the disadvantages of fossil fuels?
- Non renewable
- Releases CO2
What are the advantages of fossil fuels?
- Easy to gather
- Easy to transport
- Cheap / highly profitable
What are the disadvantages of nuclear power?
- Non renewable
- Releases radioactive waste (needs to be disposed of safely)
How is energy gathered from fossil fuels?
Fossil fuels are burnt which turns turbines, producing electricity
How is energy gathered using bio-fuels?
Plant matter, ethanol or methane used in place of fossil fuels
How is energy gathered using wind?
Using wind turbines
How is energy gathered using hydroelectric?
Using hydroelectric dams
How is geothermal energy gathered?
Heat from underground can be used to create steam, which spins turbines, producing electricity
How is energy gathered using the sun?
Using solar panels
What are the advantages of nuclear power?
- Reliable
- Produces no greenhouse gasses
What are the advantages of bio-fuel?
- Renewable
- Carbon neutral
What are the disadvantages of bio-fuel?
- Expensive
- Takes up a lot of land
What are the advantages of wind power?
- Renewable
- Produced no greenhouse gasses
- Land can still be used for farming
What are the disadvantages of wind power?
- Ugly
- Kills birds
- Only works if there is wind
What are the advantages of solar power?
- Renewable
- Low environmental impact
- Can be put on houses
What are the disadvantages of solar power?
- Only works if there is sun
- Uses up lots of farmland
What are the advantages of geothermal energy?
- Renewable
- Reliable
- Low environmental impact
What are the disadvantages of geothermal energy?
- Harmful gasses could be released
- Location specific
What are the advantages of tidal energy?
- Renewable
- Reliable
What are the disadvantages of tidal energy?
- Not many suitable locations
- Can harm marine habitats
What are the advantages of hydroelectric power?
- Renewable
- Reliable
What are the disadvantages of hydroelectric power?
- Can cause flooding
- Expensive to build the dam
Is the colour black a good absorber of heat?
Yes
Is the colour black a good emitter of heat?
Yes
Are white/shiny objects good at absorbing heat?
No
Are white/shiny objects good at emitting heat?
No
Other than releasing CO2, what is another environmental impact of burning coal?
Causes acid rain
What is power?
The rate at which energy is transferred
What causes mechanical processes to become less efficient?
When they produce heat, causing some of the energy to dissipate
Name an equivalent unit for watts
J/s (Joules per second)
What is work done?
The amount of energy transferred in order to move and object from one place to another
Can energy be created?
No
Can energy be destroyed?
No
What energy changes are involved when an object moves upwards (eg. if thrown)
Kinetic energy is transferred to gravitational potential energy
What energy changes are involved when a moving object hits a wall?
Kinetic energy is dissipated to various stores such as thermal stores
What energy changes are involved when a car is accelerating?
Chemical energy is transferred to kinetic energy
What energy changes are involved when a car is decelerating?
Kinetic energy is transferred to thermal energy
What is another name for thermal energy?
Internal energy
