P1 Flashcards
What surfaces are good absorbers and emitters of radiation?
Dark, matt surfaces
Where does conduction happen?
In solids
Why are metals good conductors?
Free elections.
What are poor conductors?
Insulators
Where does convection happen?
Fluids - liquids and gases
Why does evaporation take place?
When heated, the most energetic molecules escape from the liquid’s surface.
What happens after evaporation?
Regarding kinetic energy and temperature.
Kinetic energy of remaining molecules decreases, so temperature decreases.
How is the rate of evaporation increased?
Bigger surface area
Higher temperature
Creating a draught
How do you maximise the rate of energy transfer?
Good conductors
Painted dull black
Air flow maximised
How can you minimise the rate of energy transfer?
Good insulators
White and shiny
Prevent convection currents
What is the specific heat capacity?
The amount of energy required to raise the temperature of 1kg of a substance by 1ºC.
How much energy is needed to raise the temperature of 1kg of oil by 1ºC?
Specific heat capacity of oil: 2100J/kgºC
2100J
How much energy is needed to raise the temperature of 2kg of water by 1ºC?
Specific heat capacity of water: 4200J/kgºC
8400J
How can you minimise energy transfer in your house?
Loft insulation - conduction Cavity wall insulation - convection Double glazing - conduction Draught proofing - convection Aluminium foil behind radiators - radiation
What are forms of stored energy?
Gravitational potential energy
Elastic potential energy
Chemical energy
