To Measure The Specific Heat Capacity Of Water By The Electrical Method.

Apparatus

power pack, joulemeter, copper calorimeter, insulation, stirrer, thermometer, electronic balance.

Method

Find the mass of the empty calorimeter, .

Place enough cold water in the calorimeter to cover the heating coil.

Find the mass of the calorimeter plus water.

Calculate the mass of the water, by subtracting the previous two masses.

Set up the apparatus as in diagram.

Find the initial temperature of the water and the calorimeter.

Switch on the power. Allow the temperature of the water to rise until room temperature is midway between the initial and final temperatures of the water. Record the reading, H, on the joulemeter. Switch off the power. Record the final temperature, , of the water and calorimeter.

Calculate the change in temperature, .

Calculate the specific heat capacity of water using the equation:

Heat supplied = heat gained by water + heat gained by calorimeter

Sources of Error

• Heat may be gained from or lost to the surroundings.
• If a mercury thermometer is used, this is only accurate to the nearest degree.
• The water must be stirred before temperatures are read.

Solutions

• Ensure that room temperature is midway between the initial and final temperatures of the water.
• Use a digital thermometer.
• Stir the water before reading the thermometer.