Investigating the specific latent heat of melting ice

In a nutshell

By recording the temperature of ice melting, the specific latent heat of this process will be investigated. This is done by slowly heating the ice and recording the temperature, to plot a graph to analyse the energy supplied to the ice.

Equipment list

The following equipment list can be used to conduct the experiment to investigate specific latent heat.

Equipment	Use
Thermometer	To measure the temperature of the water and ice.
Digital balance	To measure the mass of the ice.
Stopwatch	To time the experiment.
Roughly $200\,g$ of crushed ice	To investigate specific latent heat.
Beaker	To hold the ice.
Bunsen burner	To provide thermal energy to melt the ice.
Tripod and gauze	To provide the set-up for the Bunsen burner.

Experimental variables

The independent variable is the variable you change. The dependent variable is the variable that changes depending on the other variables, and is the one you measure. The control variables are the variables that are kept constant.

Independent Variable	$Time$
Dependent Variable	$Temperature$
Control Variables	$Ice,\ current\ supplied,\ potential\ difference\ supplied$

Safety precautions

When performing experiments, it is very important to consider safety precautions. This is so that no one gets hurt or injured during the experiment.

Hazard	Risk	Safety Measure
Heater	Touching the Bunsen burner whilst it is on or just after it is switched off could result in burns.	Don't touch the heater whilst it is still hot. If burnt, run the burn under cold running water for five minutes.
Hot equipment	The equipment (Bunsen burner, beaker, etc) will remain hot for a while after it has been used.	Don't pack away immediately, wait until the equipment has cooled.
Gas	Gas could leak from the Bunsen burner connection which could be set alight resulting in a fire.	Make sure the connection to the gas tap is secure. Don't turn on the tap until needed for use.
Bunsen burner	The Bunsen burner uses a flame which could cause burns or set clothing on fire.	Only switch on once the Bunsen burner has been set up with the tripod and gauze. Tie hair back and stand up during the experiment. If burnt, run the burn under cold running water for five minutes.

Method

These are the instructions to complete the experiment. Record all measurements taken as you work through the experiment in a table.

Physics; Physics practicals; KS4 Year 10; Investigating the specific latent heat of melting ice

1.	Thermometer
2.	Beaker
3.	Crushed ice
4.	Tripod and gauze
5.	Bunsen burner
6.	Heatproof mat
7.	Stopwatch

1.	Set up the apparatus as shown in the diagram. The beaker should be filled half-way with ice.
2.	Switch on the Bunsen burner and slowly start to heat the ice.
3.	Take regular measurements of the temperature of the ice using the thermometer. Tip: Take the measurements at eye-level to avoid parallax error!
4.	Continue this until the substance has fully changed state.

Analysis

This is how you will use the data recorded to form conclusions.

1.	Plot a graph of temperature ( $y$ -axis) against time ( $x$ -axis).
2.	Compare the results of your graph with known theory. The temperature of the ice should not change whilst the ice is melting.

Conclusion

Physics; Physics practicals; KS4 Year 10; Investigating the specific latent heat of melting ice

A.	Temperature of the ice-water solution ( $\degree C$ )
B.	Time ( $s$ )
1.	Solid
2.	Melting
3.	Liquid

The graph from the measured values of the experiment should look similar to this. It should show that the temperature of the ice during the transition between ice and water does not change. However, the temperatures when the ice isn't melting and when it has fully changed to water should change linearly.

Evaluation

Once you have completed your experiment, it is important to consider how it could be improved. You should come up with ways to improve the accuracy of your values. If you got a result that seems unreasonable, think about why this was.