Latent Heat of Fusion of Ice
the essay is about atmospheric science. follow the instruction
Latent Heat of Fusion of Ice Experiment
100 mL graduated cylinder (caution – glass)
12 oz or 16 ox Styrofoam cup
thermometer and ice (to be supplied by the student)
Energy is required to change water from a solid to a liquid, i.e. to melt ice. In this experiment you will measure the amount of energy needed per gram of ice. You must remove the same amount of energy per gram if you want to turn water from a liquid into a solid (freeze water).
Before you begin the experiment you should obtain some ice.
You will need a few ice cubes or about half a cup of crushed ice.
Put the ice in a bowl and let it sit at room temperature until you notice
that it is starting to melt. This will probably take 15 or 20 minutes.
In the freezer ice is kept at a temperature well below freezing. We
need to allow the ice to sit outside the freezer long enough that it warms
up to 0o C. The ice can’t get warmer than 0o C, once it gets to 0o C it
will start to melt.
Add 200 to 250 mL of warm or hot tap water (40o C or less) to the Styrofoam cup. This warm water will be the source of the energy used to melt the ice. We keep the warm water in a Styrofoam cup so that it doesn’t lose energy to the surroundings. Keep a record of the volume of water added to the cup. Measure and record the temperature of the warm water.
Add one or two ice cubes (or about ¼ cup of crushed ice) to the warm water and stir gently with the thermometer until the ice is completely melted. Try to be sure you just add ice to the warm water and that you don’t also add water in the bowl from ice that has melted. Once the ice is melted measure and record the water temperature. If the water temperatures drops to near 0o C or if you are unable to quickly melt all of the ice, you will need to repeat the experiment. You will need to use more water, less ice, or both.
Use the graduated cylinder to measure the volume of the water
in the Styrofoam cup. This new volume will be larger than the initial
volume because ti contains the water from the melt ice. Because
water has a density of 1 g/cm3 (1 g/mL) you can use your measurement
of water volume to determine the mass of water at the start and finish
of the experiment. The differences in masses is the mass of the ice
that was melted.
Repeat the experiment at least one more time using a different amount of water, a different amount of ice, and perhaps a different initial water temperature.
Experiment Report Format
Title (5 pts) Your report should have a descriptive title
Introduction (10 pts) This is perhaps the most difficult
part of the report to write. You must have a good
understanding of the whole experiment to be able to write
a clear and complete introduction.
The introduction should explain in fairly general terms
what kind of measurement you tried to make and how
you made it. Don’t describe the experiment in detail here;
that belongs in the procedure section of your report.
In the latent heat experiment, for example, you are
trying to measure how much energy is needed to melt
ice. You need to add energy to ice to cause it to melt.
What is the source of the energy in this experiment?
Energy is often invisible. In your introduction you should
explain how you were able to measure how much energy
was added to the ice to cause it to melt.
Procedure (10 pts) Here you explain exactly how you
carried out the experiment. Someone unfamiliar with the
experiment should be able to perform it using just your
description of the procedure.
The procedure should be written in a narrative style rather
than a numbered list of steps or instructions. Pictures can be
very helpful and often save a lot of written description.
Data, Analysis, and Results (10-15 pts) Include your
original data collection sheet, not a copy. If you draw a graph,
use graph paper, make the graph large, and label the axes. You
should include an example of all but the simplest calculations.
Be sure to include units where appropriate.