Lab: Melting Ice
standard 3d,9d

Problem: How does the temperature of the surroundings affect the rate at which ice melts?

Purpose (write a purpose for this lab)

Skills Focus:
    predicting, interpreting data, inferring

Materials
    timer       2 thermometers    4 beakers      2 stirring rods           hot plate
    ice           warm water           thongs            goggles                 room temperature water (from the "tap")

Procedure
    1.  Based on your own experience, predict which ice cube will melt faster
        We predict that the ice cubes will melt faster when _______________________________

    2.  In your spiral copy the following data
 

            Data Table: ____________________________(determine an appropriate title for the table)

 
Beaker
Beginning Temperature ( oC)
Time to Melt (s)
Final Temperature  ( oC)
1
.
,
,
2
 . . .
 
    3.  Measure out 50 mL of water for each beaker.  One beaker of water will be your room temperature water and the other will need to be heated to be the warm water.
        a.  Place one of the beakers on the hot plate, plug in the hot plate.  Place a thermometer in the beaker and let it heat up to about 40-45oC
        b.  Place a thermometer in the other beaker on the table

    4.  When the water in the beaker on the hot plate reaches 40-45oC, remove the beaker from the hotplate and unplug the hot plate.

    5. Record the exact temperature of the water in each beaker as your beginning temperature.

    6.  Send the material manager to get ice as soon as the temperature for the warm water is reached.
        a.  Take the styrofoam cup to pick up two ice cube similar in size.  

    7.  Gently place one ice cube into each of the beakers with the water.
            a.  Begin timing with the timer.
            b.  Gently stir each cup with the stirring rod until the ice has completely melted.
            c.  Record the time and the temperature of the water in beaker.
            d   You may need to leave the thermometer in a while so that the temperature will have time to reach the exact temperature of the water.
            e. Continue stirring the other beaker of ice and water until the ice has completely melted.  Record the time and the temperature.

    9.  Make a  line graph using two different colors to represent the water temperature.
            What are your variables?
                    responding variable (include the unit) _______________________

                    manipulated variable (include the unit)_______________________

            What would you title the graph?

Analysis and Conclusion
Predicting :  Was your prediction in Step 1 supported by the results of the experiment?  Explain why or why not?

Interpreting Data: In which cup did the water temperature change the most?  Explain

Inferring :  The ice absorbed energy as it melted.  What was the source of that energy?

How did the added energy affect the relative freedom of motion of the water molecules?

Communicating: Get a white sheet of computer paper from me.  You will be turning this in on Monday so make sure everyone who contributed to the ideas and/or drew the picture have their name on the back of the drawing.

Draw a cartoon illustrating how  errors in measurement could have affected your conclusions in this experiment.  Tell what you would do differently if repeated the procedure.
(HINT: How well were you able to time the exact moment that each ice cube completely melted?)