Energy resources and transfers Flashcards
Energy stores
Chemical
Kinetic
Gravitational
Elastic
Thermal
Magnetic
Electrostatic
Nuclear
Energy
Cannot be created or destroyed, it can only be transferred along a pathway
Energy Pathways
Mechanically
Electrically
Heating
Radiation (light and sound)
Energy transfer diagrams
Useful energy ->
Wasted energy î
Efficiency
(Useful output energy / Input Energy) * 100
Movement of heat
Conduction
Convection
Radiation
Conduction
- Heat transfer along solids
molecules are made to vibrate as energy is transferred to them. - The heat is passed on by collisions of molecules.
- These vibrations are bigger when more energy.
Convection
- Heat transfer along gas or liquids.
- When the fluid is heated, it expands, making it less dense than colder fluid.
- The warmer fluid will start to move upwards. - This is called a convection current.
- This is how heat reaches us from radiators from the room.
Radiation
- Heat transfer through gases and space.
- Moves around in electromagnetic waves.
- Any hot object emits heat radiation; the hotter, the more radiation.
- Infra-red, too much can cause burning.
- Dark matt colours absorb AND emit the most radiation.
- Light shinny colours will reflect the most radiation
Theramal Insulation (home)
Roof - loft insulation (foam)
Walls - wall insulation (foam)
Windows - double glazing
Door - draught excluder
Floor - carpets / wooden floor
Work done equation
(J) = force (N) x distance (m)
Wd = F x d
Gravitational Potential Energy equation
GPE (J)= mass (Kg) * g (10)* height (m)
GPE = mgh
Kinetic Energy equation
KE (J)= 1/2 * mass (kg) * speed2 (m/s)
KE = 1/2 mv2
Speed equation (mass)
v = √(2*KE)/ mass
Speed equation (no mass)
v = √2gh