Specific heat capacity Flashcards
Different materials have different specific heat capacities
more energy needs to be transferred to thermal energy store of some materials to increase their temperature than others
Materials that need to gain lots of energy in their thermal energy stores to warm up transfer loads of energy when they cool down again. They can ‘store’ a lot of energy.
What is specific heat capacity and its equation ?
the amount of energy needed to raise the temperature of 1kg of a substance by 1 degree
change in thermal energy = mass (kg) x specific heat (j/kgdegree )capacity x temperature change (degree )
Investigating specific heat capacity PRACTICAL 1-4
1) you’ll need block of materials with two holes in it
2) measure mass of block and wrap it in insulating layer to reduce energy transferred from block to surrounding. Insert thermometer and heater to block
3) Measure initials temperature of block and set the potential difference of power supply to 10V . Turn on power supply and start a stop watch.
4) when you turn on the power, the current in circuit does work on the heater, transferring energy electrically from power supply to heater thermal energy store. The energy is transferred to materials thermal energy store by heating, causing materials temperature to increase
Investigating specific heat capacity PRACTICAL 5-7
5) As block heats up, take readings of temperature and current every minute for 10 min. You should find that current through circuit doesn’t change as block heats up.
6) When you’ve collected enough readings, turn off power supply. Using your measurement of current and and pd of power supply, you can calculate power supplied to heater using P=VI . You can use this to calculate how many energy E1 transferred to heater at time of each temperature reading E=PT
7) If you assume all energy supplied to heater has been transferred to bloc, you can plot graph of TES (energy transferred x axis ) against temperature
Investigating specific heat capacity PRACTICAL 8-9
8) find gradient of straight line = temperature change / change in TES
9) SHC is 1 / gradient x mass of block
repeat with different materials and see how their SHC compare
