SP3- Conservation Of Energy Flashcards
(43 cards)
What’s chemical energy
Energy is stored in food, fuel and batteries
Tell me about kinetic energy
Energy stored in moving objects
What’s thermal energy
Energy stored in hot objects
What’s strain energy or elastic potential energy
Energy stored in stretched, squashed or twisted materials
What’s gravitational energy
Energy stored in objects in high positions
What’s atomic or nuclear energy
Energy stored inside atoms
What’s light energy
Energy stored in light
What’s sound energy
Energy stored in sound
What’s a system in Physics
Describes something in which we are studying changes
Eg an electrical kettle and its surroundings form a simple system
What’s the law of conservation of energy
Energy can’t be created or destroyed, it can only be transferred from one store to another
This means the total energy transferred by a system is the same as the energy put into the system
What units do we use for measuring energy
Joules (J)
How do we represent energy stores and transfers using diagrams
Use a flow diagram showing the energy transfers
What does a sankey diagram show
Shows the amount of energy transferred - the width of the arrows represents the amount of energy in joules
What is dissipation
When something spreads out
Eg energy I can’t be used for other useful energy transfers when dissipated - it’s wasted
How can friction be reduced between moving parts
Lubrication - oil or other liquids and sometimes
Even gases can be used
What is efficiency
It’s way of describing how good a machine is at transferring energy into useful forms
The efficiency of a machine is given as a number between 0 and 1
The higher the
Number the more efficient the machine
How can we calculate efficiency
Useful energy transferred by the device divided by the total energy supplied to the device
What can reducing the amount of wasted energy mesn
It can increase the efficiency of a device or process
Eg for mechanical processes it can mean reducing friction
Also mean finding ways to make sure all the fuel in an engine is being burned or finding a way of Using the energy transferred by heating that would otherwise be wasted
What is insulation
Slows down the rate at which energy is transferred out of a house by heating
What’s a good example of a thermal conduction
In conduction, vibrations are passed on between particles in a solid
Metals are good thermal conductors and materials such as wood are poor thermal conductors
How can energy be transferred by heating
Conduction - where vibrations are passed on between particles in a solid
In convection - part of a fluid that is warmer than the rest rises and sets up a convection current
What’s the only way in which energy can be transferred in a vacuum
Radiation, infrared radiation can also pass through gases and some solid materials
It’s abstained and emitted easily by dull and dark surfaces
What’s thermal conductivity
How easily energy is transferred by heating
A low thermal conductivity means that energy is not transferred through those materials very easily by heating
Why are materials that contain air good insulators
Becuase air has a very low thermal conductivity so when it’s trapped it can’t form convection currents and so does not transfer much energy
