Ice absorbs total energy Q which from its environment to change from solid to liquid. Q is proportional to the heat of fusion h f . If the mass of the ice is m: then Q = h f m. For a closed system:
heat absorbed = heat given off. Thus:
h f m + c w m (T2 − 0) = c w m w (T1 − T2) + c r m r (T1 − T2) + q ………(1)
Where,
• m is the mass of ice
• m w is the mass of water
• m r is the mass of the reservoir and stirrer (assuming they are both made of the same material)
• c w is the specific heat of water
• c r is the specific heat of the (aluminum) reservoir
• q is the heat released by the thermometer which is equal to:
q = 1.93V (T1 − T2) ——–(2)
• V is the immersed volume of the thermometer in ml which can be determined by Archimedes’ Principle
Questions:
1) Derive an equation for the uncertainty in h f from equation 1 above
2) Why is it only the immersed volume of the thermometer that matters in equation 2 above?
