Energy Transfer By Heating Flashcards
(15 cards)
Define thermal conductivity
The ability of a material to transfer energy by heating.
Define a conductor
A material with a high thermal conductivity (it’s good at transferring heat).
Define an insulator
A material with a low thermal conductivity (it’s bad at transferring heat).
Define conduction
The transfer of energy through a material by the vibration of its atoms.
Define convection
The circulation of a fluid caused by increasing its thermal energy.
Define specific heat capacity
The amount of energy needed to raise the temperature of a 1kg substance by 1 °C.
Describe how loft insulation reduces heat loss
Made from fiberglass which has a low thermal conductivity. The material is mainly air, which stops conduction. The glass fibres stop convection.
Describe how cavity wall insulation reduces heat loss
Made from insulating foam. Contains air pockets to stop conduction.
Describe how double glazing reduces heat loss
Vacuum between two panes of glass. Reduces conduction and convection.
Describe how aluminium foil behind a radiator reduces heat loss
Shiny surface reflects heat back into the room.
Give factors that affect how quickly a substance heats up
Mass, thermal energy applied, specific heat capacity.
safety precuations to take when finding specific heat capacity
Don’t touch heater when it is on
Give heater time to cool down before packing away
insulate block to reduce the risk of eneergy being dissipated to surroundings
IN ORDER THREE EQUATIONS NEEDED TO FIND SPECIFIC HEAT CAPACITY DURING EXPERIMENT
power = currentX potential difference
(Pwatts) (amps) (volts)
ENERGY = Powerx time (seconds)
energy = massxSHCxtemperature change
What do we need to measure when calculating SHC
current reading from ammeter
voltage reading from power supply
initial temperature
final temperature
How to remember variables
CHIMES
independent _ what you change
dependent - what you measure
