Measurement of the specific latent heat of fusion of ice

When ice, at zero degrees celcius, is added to warm water, it first melts and then its temperature increases as it takes heat from the water. If this occurs in an insulated container then the heat gained by the ice is equal to the heat lost by the container and the water. The specific latent heat of fusion of ice (l) can then be calculated using the formula:

mi l + mi cw (rise in temp of melted ice) = mc cc (fall in temp of calorimeter) + mw cw (fall in temp of water)

where mi, mc and mw are the masses of ice, calorimeter and water respectively and cw and cc are the specific heat capacities of water and of the material of the calorimeter.

Procedure:

  1. Press "Copper" of "Aluminium" for the calorimeter
  2. Using the mouse, drag the calorimeter on to the top- pan balance
  3. Press "Find Mass". Record mc
  4. Press "Add Water". A random mass of water between 30 and 60g is added.
  5. Press "Find Mass". Record value and find mw
  6. Drag the calorimeter into the insulated container
  7. Press "Thermometer In". Record starting temperature
  8. Press "Add Ice". A random mass of ice between 5 g and 10 g is added. Observe the fall in temperature as the ice melts and absorbs heat. Record lowest temp.
  9. Press "Remove Thermometer"
  10. Drag the calorimeter to the balance
  11. Press "Find Mass". Subtract to find mi

Analysis:

Using the formula given above, calculate the specific latent heat of fusion of ice. Note: cw = 4180 J/kg/K, cc for copper = 390 J/kg/K, cc for aluminium = 910 J/kg/K

To repeat the experiment press "Reset" and repeat steps 1 to 11

Precautions:

  • Ensure that the ice is dried (dab it with tissue paper) before adding to the calorimeter
  • Use warmed water (about 5 deg. above room temp.) at the start of the experiment so that, on average, heat is neither lost or gained from the surroundings. This also helps the ice to melt more quickly speeding up the expt.
  • Use a well insulated calorimeter to avoid loss or gain of heat to the surroundings
  • Stir well and record the lowest temperature when all of the ice has melted