To measure the specific heat capacity of water by an electrical method

In this experiment electrical energy is supplied to a heating coil which is placed in an insulated calorimeter containing some water. Assuming that no heat is lost, all of the energy is used to heat the water and the calorimeter.

Thus: Energy supplied (in joules) = mw cw ( rise in temperature) + mc cc (rise in temperature)

Where mw and mc are the masses of water and the calorimeter, cc is the specific heat capacity of the calorimeter material

Procedure:

  1. Click in the text box and type in the mass of water in the calorimeter. (min.50g, max. 90g)
  2. Press "Copper" (or "Aluminium") to select a calorimeter
  3. Record the starting temperature, mass of water, mass of calorimeter, and the material of the calorimeter
  4. Press "Switch ON" to provide electrical energy to the heating coil
  5. After a temperature rise of approximately 10 degrees, press "Switch OFF"
  6. Record the number of joules of energy supplied and the final temperature of the water and calorimeter
  7. Press "Reset"
  8. Repeat the experiment using a variety of masses of water, increases in temperature, and also using the aluminium calorimeter

Calculations:

Note: cc (s.h.c. of copper) = 390 J/kg/K and ca (s.h.c. of aluminium) = 910 J/kg/K

Calculate the specific heat capacity of water cw using the formula given above (all other quantities are known).

Precautions:

  • Ensure that the heating element is covered with water to avoid any loss of heat energy
  • Ensure that the calorimeter is well insulated to avoid loss of heat energy
  • Stir the water throughout the experiment to ensure that the thermometer reading reflects the heat supplied
  • Use a sensitive thermometer graduated to 0.1 or 0.2 degrees. An error of 1 deg. in 10 is a large relative error.