Energy Resources And Energy Transfer Flashcards
What are the nine types of energy and give an example of each.
Electrical - electricity Light Sound Kinetic - a moving car Nuclear - nuclear fission reactor Thermal - fire Gravitational potential - water behind a dam Elastic potential - a stretched elastic band Chemical energy - a battery
What is energy conservation?
Using fewer resources because of the damage they do
No device is 100% efficient and the waste energy is …………
Always dissipated as heat
What are the three different ways heat can be transferred?
Radiation
Conduction
Convention
Explain radiation in thermal energy transfer.
Transferred by electromagnetic waves
Hotter the object the more radiation emitted
Thermal energy = infra red radiation
Explain conduction in thermal energy transfer.
Vibrating particles pass on their extra kinetic energy along bonds
Explain convection in thermal energy transfer.
Circulation of liquids and gases due to density differences
Cool air is more dense so sinks down
Hot air is less dense so forced up
How can a house be insulated to reduce heat transfer?
Loft insulation- reduces conduction and radiation
Hot water tank jacket - reduced conduction and radiation
Double glazing - reduce conduction and convection
Thick curtains
Cavity wall
Draught proofing
What is the principle of the conservation of energy?
Energy can never be created nor destroyed - only transferred from one form to another.
What is meant by the term that energy is conserved?
It can neither be created nor destroyed, it is just converted from one form to another.
What is the equation for efficiency?
Efficiency = useful energy output / total energy input
Explain the role of convection in everyday use.
Radiators - air above radiator is heated and rises, cold air displaced down and circulates over radiator to be heated
Cooling in fridge - cooling elements place at top of fridge, cooled air will sink, causing hit air to be displaced up and then cooled etc.
Hot water system - hot water heated on ground floor, rises up through pipes displacing cold water down into the water heater tank.
How is insulation used to reduce energy transfers?
Transfer method: conduction
Insulation type: vacuum layers with tiny air gaps
How it works: air / vacuum does not conduct
Transfer method: convection
Insulation type: layers with air gaps and lids on containers
How it works: stops circulation
Transfer method: radiation
Insulation type: aluminium layers
How it works: reflects Infra red radiation
What is the equation for work done?
Work done = force x distance moved.
What is work done equal to?
Energy transferred.
