| Back | Aims of the ExperimentTo determine the specific latent heat of ice Variables:Independent variable = Energy of the heater (Joulemeter) (J)Dependent variable = The temperature, T of the ice/water (°C)Control variables:Repeat readings with same energy supplied by heaterMass of ice in each set upTime for experiment in each set up
 Resolution of measuring equipment:Joulemeter = 1 JElectronic balance = 0.1 gThermometer = 0.1 °CSet up the experiment and the controlAttach the funnels to retort stands, place the filter paper inside and add a heater (also on a retort stand) inside one of the funnels - ensure the heater is not touching the funnelUse a spoon and an electronic balance to measure out 50 g of crushed ice into a beaker and pour into each funnelAdd a beaker below each funnel and place on top of an electronic balanceWait until the ice reaches 0 °C.This is when it starts to melt and water starts to drip out of both funnels into the beakers below.Check the temperature with a thermometer in each funnelTurn on the heaterSet the heater to supply 10, 000 Joules of energy to the experiment funnelWait until the reading on the Joulemeter says 10, 000 JTurn the heater offRead and record the mass of each beaker of water on each electronic balanceRepeat the experiment at least 3 times and calculate the average mass, m for the water in each beaker mA = average mass of water in beaker AmB = average mass of water in beaker BCalculate the mass of the melted ice and convert into kgΔm = mA - mBMass in g ÷ 1000 = Mass in kgCalculate the specific latent heat of fusion of ice to water using the equation ΔE = LΔmΔE = Energy supplied by the heater = 10 000 JL = Specific latent heat of fusionΔm = mass of ice
 Analysis of ResultsThe results obtained a latent heat of fusion of 330 000 JThe actual value of the latent heat of fusion for ice is 334 000 JThe percentage error in this value is
 = 1.2%Evaluating the ExperimentSystematic Errors:Make sure you zero the electronic balances when the beakers are emptyAlways check that the ice has reached 0 °C by reading the thermometer at eye levelThis experiment requires accurate determination of energy transfersTo improve the accuracy, consider applying lagging or insulation to the funnels and beakers - this will reduce the amount of energy lost to the surroundingsRandom Errors:The heater should be switched off and allowed to cool between readingsSo the rate of heating and the starting temperature of the heater is the sameCalculate the average mass of the waterThis will reduce random errors in the readingRepeat the experiment at least 3 times Safety ConsiderationsEnsure no water gets on the electronic balanceWipe up any spillages immediately and turn off the balanceDo not touch the heating element with your fingers, as it could be hot and burn your skinDo not handle ice with your bare hands, use a spoon to measure it into the beaker |
