Energy Flashcards
Name the 8 energy stores
Thermal
Kinetic
Gravitation Potential Energy
Elastic Potential Energy
Chemical
Magnetic
Electrostatic
Nuclear
How is energy transferred
Mechanically (by a force doing work), electrically (work done by moving charges), heating, radiation (light or sound)
What is a system?
A single object or a group of objects
What happens when a system changes?
Energy is transferred. It can be transferred into or away from the system between different objects in the system or between different types of energy stores
What is a closed system?
Neither matter or energy can enter or leave. The net change in the total energy of a closed system is always zero
What is work done
Energy transferred
It is done when the current flows or by a force moving an object
What is kinetic energy stores
Anything moving gains its energy from kinetic energy
Energy is transferred in when an object gains speed and transferred out when speed is reduced
What is kinetic energy dependant on?
Mass and speed
What is gravitational potential energy?
Transferred energy into the store of a raised object
What is gravitation potential energy dependant on?
Mass, height and strength of gravitational potential energy
What happens when an object falls
Energy from gravitational potential energy is transferred to kinetic energy
What is elastic potential energy?
Stretching or squishing an object
As long as the limit of proportionality has not been exceeded
What is specific heat capacity?
The total amount of energy required to raise the temperature of 1kg by 1’C
What was the conservation of energy?
Energy can be transferred usefully, stored or dissipated but can never be created or destroyed
What is power?
Rate of energy transfer or the rate of doing work
What is conduction?
The process where vibrating particles transfer energy to neighbouring particles
How is energy transferred?
Heating an object transfers to the thermal store of the object. The energy is shared across kinetic energy stores and particles in the object. The collisions of the particles transfer the energy across particles/object
What is convection?
Where energetic particles move away from hotter to cooler regions
How does convection occur?
Energy is transferred by heating to the thermal store of the liquid or gas. The energy is shared across the kinetic energy stores of the liquid or gas’ particles
Why does convection decrease the density?
The liquid or gas’ particles will move faster and increase the space between particles so the density increases
How does convection currents work?
Warm air rises as cooler air sinks creating a cycle of air
How to reduce energy loss
Lubrication and thermal insulation
How does lubrication reduce frictional forces?
The lubricants reduce friction between the objects surfaces when they move and can easily flow between objects.
How does insulation reduce energy tranfser
Thick walls made from materials with low thermal conductivity meaning there is a slower rate of energy transfer.
Example of thermal insulation
Cavity walls that with an air gap that allows energy transfer by convection
Loft insulation
Double glazed windows
Draught excluders reduce energy transfer by convection
