Energy Transfer Flashcards
what are the 9 energy stores
STEELPACK
Sound
Thermal
Elastic potential
Electric
Light
Potential (GPE)
Atomic - Nuclear
Chemical
Kinetic
what is wasted energy
Wasted energy = energy that is transferred to stores other than the desired store
when a car starts, u need kinetic energy for movement, but you also get heat
write the energy flowchart for a person cycling up a hill
A person cycling up a hill
Chemical –> kinetic –> GPE –> thermal
Principle of conservation of energy = energy cannot be created or destroyed, only transferred
what happens when energy is used, (dissipation)
When energy has been transferred through some stores, it can dissipate (spreads out into the surroundings)
Once energy dissipates, it becomes too spread out to be able to use
what do sankey diagrams show
Sankey diagrams show all the stores of energy in a process, and it shows how much of the inputed energy goes into each store
Sankey is drawn to scale - the sizes of the arrows reflect the sizes of the energy store
how many celsius is 0 kelvin
0K=-273 degrees celsiusot
what are the 3 forms of energy transfer
Three forms of thermal transfer (energy transfer of thermal energy) are conduction, convection and radiation
what is conduction
Conduction: thermal energy transfers partially to kinetic to thermal –> the particles in a substance vibrate, and the vibration travels along the substance - heat travels along the substance
why Metals are much better at thermal conduction than other elements
Metals are much better at thermal conduction than other metals –> the delocalised electrons can travel throughout the metal rapidly, letting the transfer of energy take place faster
what is convection
Convection:
Convection takes place within kettles, and with radiators
Convection = the thermal transfer of energy within fluids
Fluids = liquids and gases (they both flow)
what does heat rise and cold sink
When something is hot, it expands - becomes less dense - this is why ‘heat rises’
When something is cold, it contracts - this is why cold water/cold air descends
In a kettle:
descrive convection in a kettle
The water at the bottom is heated, and so it rises, and the water previously at the top takes its place.
The hot water at the top cools down, distributing its heat to surrounding water particles, at the same time that the cold water particles at the bottom heat up by the kettle
So, at the same time, the cooled water from the top becomes dense and sinks, and the heated water at the bottom expands, ands so rises
This cycle is called a convection current
This repeats until all the water particles are very h
what is a convection current
the cycle of hot rising and cold falling, when cold falls it becomes hot and when hot rises the hot gives of its thermal energy to surroundings and becomes cold
what do all objects emit
All objects emit infrared radiation
The higher the temperature of an object, the more infrared it emits in a given time
A body at constant temperature emits and absorbs IR at the same rate
what colour abosrbs the most infrared radiation
Matt black absorbs and emits IR the most effectively
what affects rate of thermal energy transfer
The greater the temperature difference between two substances, the faster the rate of thermal transfer
when you heat something, why does it turn red
When heating a substance up, the radiation it emits can start to go into the visible light spectrum - metals glow red when heated a lot
what is the difference between infrared radiators and convection radiators
There are radiators which heat up homes using infrared radiation
With infrared radiators, they emit IR out in straight lines, and have an immediate effect, whereas convection current radiators take longer to heat the room up.
where is enegry from that is used in homes
Our energy used in the home comes from burning fossil fuels
what are the 3 fossil fuels
Fossil fuels = coal, oil and gas
what are There are 2 big problems with using fossil fuels:
Non-renewable - so they can soon run out
Burning fossil fuels emits greenhouse gases
what are the 3 greenhouse gases
Greenhouse gases:
CO2, methane and water vapour
what do greenhouses do
Greenhouse gases= trap (infrared) radiation in the atmosphere
why are greenhouses gases harmful
Up to a certain amount, this was good - it is our atmosphere with the greenhouse gases that allowed Earth to become warm enough to sustsain life
Now, it is leading to global warming - the Earth’s temperature has been rising, with the increase of greenhouse gases in the atmosphere
