Energy Flashcards
what is the unit of energy?
Joule
System:
a connected set of resources and processes
The law of conservation of energy:
the law that states energy can neither be created or destroyed. Only transferred e.g. solar energy or transformed e.g. hydroelectricity
useful energy
when energy is captured for a purpose
wasteful energy:
When energy is produced as a side effect and lost from a system
Energy efficiency formula
Efficiency of energy use = useful energy output / total input energy x 100/1 %
Qualitative measurements:
measurement that we describe such as hot, cold
Quantitive measurements:
measurements that we can give a numeric value to such as degrees celsius, metres, hertz etc.
What are the two scales for measuring temperature:
- Degrees celsius
2. Kelvin
How to calculate Kelvin:
temperature (K) = temperature C + 273
what is thermal energy?
the energy of the particles of which a substance is made; heat energy
What is thermal equilibrium?
the result of two interacting systems coming to the same temperature
what is conduction?
The transfer of heat energy by direct contact between particles in systems (occurs in solids)
What is convection?
the bulk movement of a fluid that carries thermal energy from a system
what is radiation?
The infrared electromagnetic radiation that carries thermal energy from a system.
input:
a resource that flows into a system
output:
the intended product of a system
local system:
a defined system connected to other systems
surrounding system:
the immediate system into which emissions from a local system are transferred
universe:
the ultimate system
Kinetic energy:
energy of movement
potential energy:
energy other than kinetic energy that is ready to be transferred or transformed
calibration points:
a value of a quantity that is used to define a scale
car safety systems:
all safety systems transfer and transform energy so that it has the least dangerous effect on people.
work:
the force applied over a distance; a way of transferring mechanical energy; w = F x d
WORK DONE = ENERGY TRANSFERRED
About sankey diagrams:
- way of showing the conservation of energy
- show energy transfers taking place
Explain what is meant by the term energy
Energy is the capacity to do work
What is an energy transfer?
The energy is sent somewhere else e.g. guitar transfers sound to air
What is energy transformation?
Energy is changed e.g. solar to heat
Show the energy transformations of an:
- Playing music on an iPod
- Hydroelectricity
Electrical —-> Heat and sound
Potential—–> Kinetics ——> Electrical
—> Sound
For the following, provide the energy type, description and examples.
- Potential
- Kinetic
- Thermal
Potential - Due to state or position - water in dam
Kinetic - Due to movement - car moving
Thermal - due to vibration of particles - microwave oven
state the units of energy
Joules or kilojoules
How to convert Celsius into Fahrenheit:
Temperature (F) = Temperature (C) x 1.8 + 32
Explain how conduction transfers thermal energy
Due to movement (kinetic energy) of particles (solids)
Explain how convection transfers thermal energy
Due to density differences (liquids)
Explain how radiation transfers thermal energy
Thermal energy carried by electromagnetic radiation (gases/space)
write the general chemical reaction for hydrocarbons burning:
hydrocarbon + oxygen —-> carbon dioxide + water + Thermal energy
outline how a seat belt helps to save lives:
They restrain the occupants so they do not bounce around in the car or get thrown out, therefore stop injuries
Outline how an airbag helps to save lives:
They inflate rapidly on impact to stop people sustaining injuries from the driving wheel
Outline how the crumple zone helps to save lives:
These are designed to absorb the force of the impact and thus preserve the main body of the car
