Energy Conservation Flashcards
Energy stores
-kinetic
-chemical
-thermal
-internal
-GPE
-magnetic
-electrostatic
-nuclear
Principle of conservation of energy
The total amount of energy in a closed system is constant. Energy cannot be created or destroyed, only converted from one form to another
Energy transfer examples
Kettle - electrostatic —> thermal
Log fire - chemical —> thermal
Kicking a ball - KE —> GPE
Dissipation of energy
Spreading out into the surroundings (eg. Fiction - dissipation of energy from heat)
Reducing energy dissipation
Lubrication - reduces friction
Wheels - reduce friction
Streamlining - reduces air resistance
Thermal insulation - reduces rate thermal energy to lost to surroundings
Low resistance cables - less energy dissipated as heat
Energy efficiency
Energy efficiency = useful output energy / total input energy
Thermal insulation - housing
-felt loft installation
-cavity wall insulation
-carpets
-double/ triple glazed windows
Materials as thermal conductors practical
Independent variable - insulation (eg. Black paper, foil)
Dependant variable - temperature decrease
Control variables - initial temperature, volume of water