Specific heat capacity of water

AIM

The aim of this experiment is to measure the specific heat capacity of water (c_W) using an electrical method.

YOU WILL NEED

A copper or aluminium calorimeter, a muff, an electrical immersion heater, a voltmeter, an ammeter, connecting leads, a low voltage power supply, a thermometer (0 – 50^oC), a stop watch.

WHAT TO DO

Measure the mass of the calorimeter (M_C) and fill it with a known mass of water (M_W). Record the initial water temperature (θ₁).

Set up the apparatus as shown in Figure 1.

Switch on the heater allow it to heat up so that it is slightly warm to the touch and then put it in the water. Place the muff over the calorimeter and heat the water for a measured time (t).

Measure the final temperature of the water (θ₂).

Record the voltage (V) and current (I), this may need to be adjusted throughout the experiment so that the power input remains constant.

ANALYSIS AND CONCLUSIONS

Calculate the specific heat capacity of water from the equation:

VIt = M_Cc_C(θ2 – θ1) + M_Wc_W(θ2 – θ1)

Where c_C is the specific heat capacity of the material of the calorimeter.

Record any sources of error which you consider will affect your result and suggest how they might be reduced.

Repeat the experiment with a different mass of water and then with other liquids.

Note: These instructions are only intended as an outline of experimental procedure. You should consult your teacher for a more detailed version before carrying out the experiment.