P1.1 - Energy transfer by heating
- Created by: AbiJohnson
- Created on: 24-10-15 16:32
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- P1.1 - Energy transfer by heating
- Evaporation & Condensation
- Evaporation = liquid turns into gas
- energetic molecules escape- enter the air
- rate increases: larger surface area - larger temprature
- energetic molecules escape- enter the air
- Condensation = gas turns into liquid
- rate increases: large surface area - reducing surface temp.
- Evaporation = liquid turns into gas
- Surfaces & Radiation
- Dark matte- good absorber of infrared radiation- good emitters
- Light, shiny- good reflectors of infrared readiation
- Conduction
- gases=poor concutors
- ALL metals=good conductors
- one end of solid heated - gain kinetic energy - vibrate - energy transferred
- Occurs in metals
- free electrons gain kinetic energy - collide with particles
- Occurs in metals
- Infrared Radiation
- detect on skin - warmth
- waves are part of the electromagnetic spectrum
- the hotter the object = the more infrared radiation it emits
- Specific heat capacity
- E=m x c x
- greater mass=more energy required
- Specific Heat Capacity
- the greater the SHC = the more energy required
- transfer energy = increase temp.
- Energy transfer by design
- minimise tranfser - white & shiny
- maximize - dull & black
- greater the temp = greater energy transfer
- Vacuum flask: Double walled glass - sponge pad - spring support- inside silvered to stop radiation
- minimise tranfser - white & shiny
- States of matter
- Solids - vibrate
- fixed shape
- Liquid - move about - flow
- Gas - far apart- flows
- Density is less that liquid or solid
- Solids - vibrate
- Convection
- occurs in fluids
- heated + expands
- becomes less dense and rises
- = convection currents
- transfers energy throughout fluid
- = convection currents
- becomes less dense and rises
- heated + expands
- occurs in fluids
- Heating & insulating buildings
- U Value
- how much energy goes through a material
- lower U value = better insulation
- loft insulation
- cavity wall insulation
- double glazing
- aluminium foil behind radiators
- double glazing
- cavity wall insulation
- U Value
- Evaporation & Condensation
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