Thermal Energy and Heat

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					Thermal Energy and Heat                                                      Teacher’s Notes

In Hot Water
The following steps will walk you through the       own insulating device. Remind students to
Chapter Project. Use the hints and detailed         refer to the hints in the Project Overview as
instructions as you guide your students             they plan and carry out the project.
through experimental design, materials
testing, device design and construction, and        Materials and Preparation
presentation.
                                                    Each student will need an empty aluminum
Chapter Project Overview                            soda can. Alcohol thermometers, funnels to
                                                    pour hot water into cans, tongs or hot pads,
In this project, students will conduct
                                                    and a source of hot water, such as a coffee urn
experiments to learn about heat loss and will
                                                    should be available.
construct an insulating device for a 355-ml
aluminum can.                                           Gather an assortment of materials for
                                                    students to test, such as aluminum foil,
     To introduce the project and stimulate
                                                    newspaper, packing peanuts, cardboard, nylon
student interest, perform the following
                                                    cloth, canvas cloth, cotton balls, plastic wrap,
demonstration. Bring an insulated container
                                                    foam board, and wood chips. Encourage
of hot water to class the day before you begin
                                                    students to suggest and use other materials as
the project. Measure the temperature of the
                                                    well.
water. Leave the container in the classroom
until the next day. Measure the temperature of          Caution students to use extreme care
the water again. Ask students why the               when transporting hot water around the
temperature of the water decreased. Explain         classroom and when pouring hot water into
to students that even the best insulators           containers. Students should wear goggles and
cannot keep hot water warm indefinitely.            oven mitts.
Eventually the heat of the water will be                 Students could start building their device
transferred to its surroundings (the air in the     in the early stages of the project. This tests
room) until the water and its surroundings are      intuitive knowledge without giving them a
the same temperature.                               chance to learn through experiment.
     Have students read the Project Overview.
Review the Project Rules and hand out the           Keep Students on Track—Tasks 1–3
Scoring Rubric. Discuss with students what          Because the testing requires the use of
will be expected of them.                           thermometers, this part of the project maybe
    Set a deadline for the project presentation     better done in class. Many of the experiments
and interim dates for the different project         could involve setting up the can at the
tasks. Encourage students to copy the dates         beginning of class and then checking
on the Project Timeline.                            temperatures at the end of class.
     If you have grouped students during the             This step may be difficult for some
initial testing phase of the project, have each     students because they are expected to design
group come up with an experimental plan and         experiments. During a discussion, help
then have each student in a group test one or       students see that their experiments will fall
two materials or design features using the          into two areas: the type of material used for
plan. To ensure that every student will have        the insulation and the location and thickness
ample opportunity to participate in                 of the insulation. Students should measure the
experimental planning and testing, each group       insulation ability of many different materials
should consist of no more than four students.       and designs to help them in designing their
                                                    own container and in predicting the insulating
    Distribute copies of Project Worksheet          properties of other students’ containers.
1. This worksheet will help students collect
data during the testing part of the project.
Project Worksheet 2 will help students
design their



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                                     Thermal Energy and Heat
Thermal Energy and Heat                                                      Teacher’s Notes

Worksheet 1 will help students decide which               Students should present their containers
materials and design features work best.             to the class and explain why they chose the
    Check students’ experimental plans.              materials and features that they did. When
Have they identified controls? Do they know          making predictions, students should look for
what will be manipulated? Look over the              similarities to designs and materials they
designs to determine what other materials            tested. Each student should predict the final
might be needed if currently unavailable in          temperature of his or her own project as well
the classroom. Decide how much time you              as the final temperature for 3 to 5 other
are going to allow students to test materials.       projects. While the class is waiting for final
Some students may have to rethink their              temperatures, predictions can be posted.
experimental designs if given a time limit.              Extension
Keep Students on Track—                              When the devices are tested, pour water into
                                                     an uninsulated can to act as a control.
Tasks 4–6                                            Subtract the final temperature of the water in
Have students discuss the results of their           the control can from the starting temperature
experiments in small groups. Tell students to        to calculate the maximum temperature drop.
use Worksheet 2 during these discussions.            You could look at each student’s device from
Not everyone will have tested all possible           the standpoint of percent of maximum drop.
variables. Consider having a class discussion        For example, suppose the maximum drop
to allow students to have access to all of the       was 45°C and a student’s device lost 15°C.
data. Point out certain trends that the data are     As a percent of the maximum, the drop was
likely to support. For example, lids are             33% (15°C/45°C). The lower the percentage,
important and insulation over a particular           the better the device was at insulating the
thickness is not very helpful.                       can.
     Decide how much time, if any, you are
going to allow students to work on their
containers in class. Remind students of the
date on which their containers must be
finished. Remind them that they need to test
their containers with water at different
starting temperatures.
Chapter Project Wrap Up
Make arrangements to have a large quantity
of hot water at constant temperature
available on the day the devices are
presented. A large coffee urn works well. At
the beginning of class, quickly fill the cans in
each of the students’ containers. All cans
should be filled with water that is the same
temperature; 80-90°C should work well.
Take care when pouring the water to not
burn yourself or students. Students should
use the temperature of the water reservoir as
the starting temperature. Tell them to stir the
water in the cans before taking the final
temperature.




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                                      Thermal Energy and Heat
Name__________________________________Date_________________Class____________________


PROJECT OVERVIEW
In Hot Water
In this chapter you will learn about temperature, thermal energy, and heat and how these
concepts are related. Keep in mind what you learn because you will be using this information to
design a container to slow the loss of heat from a 355-mL aluminum can of hot water.

      This project has two parts. In the first part, you will design and conduct experiments to
learn more about materials that can help prevent heat loss. In addition, your experiments will
investigate whether certain container designs slow heat loss more than other designs.
     The second part of the project involves building a container that insulates an aluminum
can of hot water. Once you have built your device, you should test it with various water
temperatures.
     For your presentation, your teacher will fill your can with hot water of a known
temperature. At the end of the class period, the temperature of the water in your can will be
measured. If the difference between the starting and ending temperatures is small, your
container is a good insulator! You will be asked to predict the final temperature of the water in
your device and in the devices of other students. To make your predictions, you will need to
review your notes and recall what you learned in your experiments.

Project Rules
 • Have your teacher approve your plans before you begin your experiments.
 • Your container must be something you assembled. You cannot use ready- made or
   manufactured devices. This excludes foam drink holders and commercial bottles or cups.
   In addition, you may not use electric current or heating chemicals.
 • Your container should keep the water sample as hot as possible while using the thinnest
   amount of insulation. The insulation must be no thicker than 3 cm.
 • The opening of the can must be easily reached so that hot water can be poured in.
   However, you may cover the opening of the can during the cooling period.
 • The aluminum can may not have any other holes besides the opening in the top.
 • When you design your project, keep in mind that a thermometer will be inserted through
   the opening in the top to measure the final temperature.




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                                     Thermal Energy and Heat
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Safety
You will be working with hot containers and water that can burn skin. Be careful,
especially when moving the hot water. Wear goggles to protect your eyes and oven mitts
to protect your hands.

Suggested Materials
In your group, you will need to test many different materials for their ability to insulate.
Examples include: aluminum foil, newspaper, packing peanuts, cardboard, nylon cloth, canvas
cloth, cotton balls, plastic wrap, foam board, and wood chips. You can try other materials as
well.

Project Hints
 • Record the data from your experiments as outlined in Project Worksheet 1.
 • Share the results of your experiments with other students and rank the materials and
   container designs with respect to their ability to minimize heat loss (see Worksheet 1).
   Each person can do a different experiment and learn from each other’s work.
 • Use Project Worksheet 2 to help you with the design and construction of your device.
 • Plan on building your insulating device several days before it is due. You will need time to
   test your device with different temperatures of water. Record the temperature of the water
   in the can every 10 minutes for 40 minutes. You can then make a graph by plotting
   temperature against time. This graph will help you make predictions.
 • Throughout the project, keep track of what you have learned about insulation devices. This
   will help you to predict the final temperature of the water in your classmates’ devices.

Project Timeline
 Task                                                             Due Date
 1. Plans for heat loss experiments completed.           _______________________
 2. Experiments completed.                               _______________________
 3. Project Worksheet 1 completed.                       _______________________
 4. Project Worksheet 2 completed.                       _______________________
 5. Insulating device constructed.                       _______________________
 6. Tests of insulating device completed.                _______________________
 7. Device presented and tested in class.                _______________________
 8. Predictions made.                                    _______________________




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                                     Thermal Energy and Heat
Name__________________________________Date_________________Class____________________


PROJECT WORKSHEET 1
In Hot Water
Some of your experiments should help you to determine which types of materials make the best
insulators. Make a table similar to the one below on a separate sheet of paper. Add a separate
row for each material you test. Use it to record your data.

Material Tested       Time                       Temp. (°C)                  Insulating Ability
                                                                             Rank
                      Start______________        Start______________
                      End______________      End______________
                      Elapsed (mins) _______ Change _____________




 1. Write the name of the material to be tested in the first column.
 2. Record starting and ending times of your experiment in the second column. Use these
    times to calculate the elapsed time in minutes. You should try to keep the elapsed
    time the same for all materials.
 3. In column three, record the starting, ending, and change in temperature of the water in the
    can. The starting temperature should be the same or nearly the same for all materials
    tested.
 4. Once you have all of your data, determine a way to rank the materials in terms of their
    insulating ability.
You will also need to conduct experiments to determine the best location and thickness for the
insulation. Make a table similar to the one below on a separate sheet of paper. Add a separate
row for each design you test. Use it to record your group’s data.

Design               Time                        Temp. (°C)                   Insulating Ability
                                                                              Rank
                     Start______________         Start______________
                     End______________           End______________
                     Elapsed (mins) _______      Change _____________




 1. In the first column give a description of the design being tested (with or without lid,
    thickness of insulation, with or without bottom, and so on).
 2. The elapsed time and starting temperature of the water should be the same or nearly the
    same for each design.
 3. Once you have all of your data, determine a way to rank the designs in terms of their
    insulating ability.




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                                    Thermal Energy and Heat
Name__________________________________Date_________________Class____________________


PROJECT WORKSHEET 2
In Hot Water
Answer the following questions to help you design your insulating device.

 1. Why was it important to keep the elapsed time and the starting temperature of each of your
    experiments the same or nearly the same?




 2. What method did you use to rank the materials and designs that you tested?




 3. Which three materials that you tested were the best at insulating the hot water? Do these
    materials have anything in common? What are some similar materials?




 4. Which three design features that you tested were the best at insulating the hot water? Can
    you think of a way to include all three design features in your device?




 5. Using the results of your experiments, choose one or more materials that are good
    insulators and choose the design features that you want to use. Make a sketch of your plan
    for your container. Label its important features.




 6. On a separate sheet of paper, make a list of the materials you will need to construct your
    device. Be sure to identify other materials that may be needed during construction such as
    tape, string, or glue.




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                                    Thermal Energy and Heat
Name__________________________________Date_________________Class____________________




SCORING RUBRIC
In Hot Water
In evaluating how well you complete the Chapter Project, your teacher will judge
your work in the following categories. In each, a score of 4 is the best rating.

                                       4                              3                               2                              1
Developing                Experimental design            Design shows good              Design shows partial           Design shows limited
Experimental Design       clearly shows                  understanding of the           understanding of the           understanding of the
and Testing Materials     understanding of the           value of keeping some          value of keeping some          value of keeping some
                          value of keeping some          variables constant.            variables constant.            variables constant.
                          variables constant.            Experiments test both          Experiments test either        Experiments test either
                          Experiments test both          materials and design           materials or design            materials or design
                          materials and design           features.                      features, but not both.        features, but not both.
                          features.
Designing, Building,      Device adheres to              Device adheres to project      Device adheres to project      Device clearly violates
and Testing the           project rules. Device is       rules. Device is a good        rules. Device is a poor        one or more project rules.
Insulation Device         an excellent insulator.        insulator. Testing of          insulator. Testing of          Testing of device is
                          Complete testing of            device performed on time.      device is incomplete.          incomplete.
                          device performed on
                          time.
Predicting Results        Uses knowledge learned in      Uses knowledge learned in      Uses knowledge learned in      Guesses rather than uses
                          project. Accurately predicts   project. Accurately predicts   project. Accurately predicts   knowledge learned in
                          final temperature of several   final temperature of two or    final temperature of own       project. Predictions of all
                          different device designs,      more device designs,           device only.                   devices, including own,
                          including own.                 including own.                                                are inaccurate.
Working                   Takes a lead in group          Participates in all aspects    Participates in most           Participates minimally
Cooperatively             planning. Effectively          of group planning.             aspects of group planning.     in group planning.
(optional)                communicates container         Communicates most              Communicates some              Communicates few
                          features to class.             container features to class.   container features to class.   container features to
                                                                                                                       class.




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                                                              Thermal Energy and Heat

				
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