Specific Heat Capacity

In simple terms it means, how hard it is to heat something up.

Different Materials have Different Specific Heat Capacities

  1. More energy needs to be transferred to the thermal energy store of some materials to increase their temperature than others, e.g. you need 4,200J to warm 1kg of water by 1c, but only 139J to warm 1kg of mercury.
  2. Materials that need to gain lots of energy in their thermal energy stores to warm up also transfer loads of energy when they cool down again. They can ‘store’ a lot of energy.
  3. Specific heat capacity is the amount of energy needed to raise the temperature of 1kg of a substance by 1c.

Formula: CE = mcC0

Change in thermal energy= Mass(kg) x Specific Heat Capacity(J/kgc) x Change in temperature

You can investigate Specific Heat Capacity

  1. To investigate a solid material(e.g. Copper), you’ll need a block of the material with two holes in it(for the heater and thermometer to go into)
  2. Measure the mass of the block, then wrap it in an insulating layer to reduce the energy dissipating from the block into the surroundings. Insert the thermometer and heater.
  3. Measure the initial temperature of the block and set the potential difference,V, of the power supply to 10V.
  4. When you turn on the power, the current in the circuit does work, transferring energy electrically from the power supply to the heaters thermal energy store. This causes the material’s temperature to increase.
  5. Take readings as the block heats up of the temperature and current every 10 minutes. The reading though the current shouldn’t change.
  6. After 10 readings, turn off the power supply. Using your measurements of the current, and the potential difference of the power supply, you can calculate the energy transferred to the heater. E=Pt
  7. You can then plot a graph of energy transferred to the thermal energy store of the block against temperature.
  8. To find the gradient you can use the equation Change in Temperature / Change in Energy
  9. To calculate the specific heat capacity do 1/(gradient x the mass of the block).

You can then repeat the experiment with different materials to see how their specific heat capacity compares.