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					                  Specific Heat Capacity
                       Lesson Plan




Prepared By:
Koh Chia Ho, Jared
054554L23
S7904178E
Lecturer: Dr Yap
Submission Date: 17 Oct 2005
Specific Heat Capacity


Topic:                          Thermal Properties of Matter

Subtopics:                      Specific Heat Capacity

Duration:                       2 periods (70 minutes)

Level:                          Secondary 3 Express (Pure Physics)

Venue:                          Physics Laboratory


Lesson Prerequisites:

Students have learnt:

a) A rise in average kinetic energy of molecules in a substance corresponds to a rise in its
    temperature.
b) Thermal energy is transferred from a region of higher temperature to a region of lower
    temperature.
c) The motions of particles of substances in the three phases in terms of Brownian motion.
d) The Principle of Conservation of energy in the case of heating where the amount of heat energy
    supplied to a substance is equal to the amount of heat energy gained by it.

Specific Instructional Objectives for the Lesson:

At the end of the lesson, students should be able to:

a) Define the terms heat capacity and specific heat capacity.
b) Recall the relationship thermal energy = mass  specific heat capacity  change in temperature
c) Apply the relationship between thermal energy, mass, specific heat capacity and change in
    temperature to new situations or to solve related problems
d) Apply their knowledge of the high heat capacity of water to everyday applications.

Learning Aids & Resources:

         Non IT:         i)     1 metal spoon
                         ii)    1 plastic spoon
                         iii)   1 candle
                         iv)    1 balloon filled with air
                         v)     1 balloon half filled with water, half filled with air
                         vi)    1 beaker containing 400ml of water
                         vii)   1 beaker containing 400ml of cooking oil


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  Specific Heat Capacity


                           viii)     2 immersion heaters
                           ix)       Data logger with 2 temperature sensors

          IT:              i)        PowerPoint Slides
                           ii)       Java applet on colorimetry

          Worksheet: Worksheet 1

  New Concepts/Terms:
  Heat capacity, specific heat capacity.

  Concept Map:



                                           Increases or decreases    Heat absorbed or
       Internal energy of matter
                                                                       released, Q
                    Which in turn increases
                    or decreases


Potential energy                                     Heat                     C           Specific Heat
     (due to          Kinetic energy              Capacity, C            c                Capacity, c
                                                                              m
 intermolecular       (due to motion)                  Q  C        where m = mass         Q  mc
      force)




                                   Change in kinetic
                                   energy causes                    Temperature change
                                                                       in matter, 
  Set Induction and Use of Trigger Activity:

     Demonstrate that despite students’ intuition, a heated water balloon does not burst due to the
      high heat capacity of water.
     Students will be rooting for the water balloon to burst and wetting the teacher in the process.
      When this does not happen, it throws students into a cognitive disequilibrium. They would be
      very interested to learn why, and as a result, be more attentive during the lesson.

  Lesson Development:

  1) Everyday applications
     Stimulate students’ minds by recalling their past knowledge of heat insulators and conductors
     and how it will be tied to heat capacity.



  2) Use of IT - Interactive applet demonstration



                                                                2
Specific Heat Capacity


    Stimulate heating different amounts of water. As the science laboratory may not have
    computers for students to use, this is done via teacher demonstration. An applet is used because
    this activity is an intuitive concept that students may encounter in their daily lives. The applet is
    able to produce precise readings that students need to perform calculations on later in the
    lesson. Demonstration is done with guided questions to engage the students to think about the
    topic. This also serves as a simple introduction to the concept of having different heat capacities
    for different amounts of the same substance and sets the pace for the whole lesson. Later on,
    students can revisit this applet to find the specific heat capacity of water.

3) Experimentation
   Experimentation to investigate the different rates of heating between oil and water. This allows
   students to observe first hand that for the same amount of heat supplied, different substances
   show a different rise in temperature. They are then introduced to the definition of heat capacity.
   Students can also appreciate the use of cooking oil in cooking because it has a low heat
   capacity, so we are able to cook food faster.
   If dataloggers are not available for all students they will have to use thermometers to record the
   temperature. This also promotes data recording skills in the students.

4) Student participation in learning the definition and calculation of experimental results.
   Through the use of scaffolding questions, students come up with the definition of heat capacity
   and specific heat capacity themselves. This helps them to retain this new information better.
   They then practice what they have learnt in doing some calculations based on their experimental
   results. This helps give meaning to why they were asked to perform the experiment.

Lesson Closure:

Ask students to provide an answer to the induction activity performed at the beginning of class
based on what they had just learnt. This shows whether students understood the lesson.
Use of a concept map to see how what they had learnt fits into the whole picture. This is followed
by a quick summary, and students are asked to do some homework questions before the next
lesson.

Reference:

1) GCE ‘O’ Levels Physics Syllabus (5052)
2) C. Chew, Leong S.C., Chow S.F. (2000) Physics A Course for ‘O’ Level (2nd ed). Singapore:
   Times Media Private Limited
3) Calorimetry Applet
   http://www.chm.davidson.edu/java/calorimetry/calorimetry.html
4) Physics Lesson Plan for Thermal Properties of Matter Set E
   http://teachersportal.nie.edu.sg/kcyap/Physics2002/O%20Level/Thermal%20Properties%20of%
   20Matter/Set%20E%20-
   %20Specific%20Heat%20Capacity/Specific%20Heat%20Capacity%20-
   %20Lesson%20Plan%20(Set%20E).doc
5) UW Physics Lecture Demonstrations – Heat capacity of a water balloon
   http://www.phys.washington.edu/facilities/lectdemo/thermo.html#cap




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Specific Heat Capacity




Lesson Plan

    Stages                     Activities/Procedures                           Resources               Rationale
Set Induction-      Show a balloon filled with air, and a balloon half-     1 balloon filled       Generate interest in
Demo                 filled with water to the students.                      with air               the topic by
                    Ask students what they would expect if the balloon      1 balloon half-        showing a
5 min                filled with air is heated by the lighted candle.        filled with water,     demonstration.
                    Expect students to say the balloon will burst.          half-filled with air   Students will be
                    Demonstrate that the balloon will burst by bringing     1 lighted candle       hoping the water
                     it near the lighter from the top.                                              balloon bursts thus
                    Next, show students the balloon half-filled with        PowerPoint             wetting the teacher,
                     water and ask them the same question.                   Slides                 but that will not
                    Expect a mixture of answers: some say it will burst,                           happen.
                     some will say it will not.
                    Bring the balloon towards the lighter from the top                             Only give the
                     slowly making sure the flame does not touch the                                answer at the end
                     sides of the balloon, just the bottom. Show that the                           so that they will be
                     balloon does not burst.                                                        attentive during the
                    Ask students to think about the reasons why the                                lesson.
                     balloon does not burst.                                                        Feeling the
                    Tell the students that at the end of the lesson, they                          difference
                     will be able to answer the question.                                           themselves creates
                                                                                                    a lasting
                 Recall previous knowledge                                                          impression.
                  Show the plastic spoon and metal spoon to the
                    class.                                                                          Let students recall
                  Ask students whether the spoons are at the same                                  their previous
                    temperature.                                             Plastic spoon          knowledge of heat
                  Lead students to respond that both spoons are at          Metal spoon            conductors. Link
                    room temperature.                                                               the idea of heat
                  Touch the spoons one after another on most of the         PowerPoint             conductors and
                    students’ hands. Ask them whether they feel a            Slides                 insulators to the
                    difference between the two materials.                                           property of heat
                  Lead students to recall a concept they had                                       capacity.
                    previously learnt – heat conductors and heat
                    insulators.
                  Lead students to explain the phenomenon they had
                    just experienced based on heat conductance – good
                    heat conductors conduct heat away from our skin
                    faster, making us feel cold.
                  Ask students what kind of material makes up the
                    frying pan’s handle and the actual pan itself.
                    Highlight that this is an application of heat
                    conductors and insulators.
                  Ask students why is it when the same amount of                                   *Note:
                    heat is supplied to a conductor and an insulator,                               Microteaching
                    one becomes hotter than the other. Tell them that                               Segment
                    this is also another property that they are going to
                    learn.




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Specific Heat Capacity


    Stages                       Activities/Procedures                          Resources            Rationale
                   Introductory investigation
Lesson              Show applet on calorimetry to students.                  Calorimetry         An applet is used
Development 1-      On the applet, heat up 20 ml of water, power             applet.             in this case because
Demo and                100W, for 10 sec and ask students what is the                             it stimulates the
introduction of         temperature rise (7.28 degrees Celsius).                                  heating process
concept of heat     Ask students what they would expect if we double         Worksheet           faster than actually
capacity                the amount of water to be heated, all else remain                         performing the
                        the same. Lead students to intuitively guess that     PowerPoint          experiment.
10 min                  they expect a lower temperature rise. Show that       Slides              Moreover this
                        their guess is correct via the applet (4.52 degrees                       property is intuitive
                        Celsius raise).                                                           so there is no need
                    Remind students to fill in the readings in the applet                        to perform the
                        into the worksheet                                                        actual experiment.
                    Explain to students that when we supply the same
                        amount of heat to different amounts of water, the                         Start with learning
                        temperature rise is different. This is because a                          about different heat
                        larger volume of water can absorb more heat before                        capacities between
                        raising its temperature – it has a larger heat                            different
                        capacity.                                                                 substances first.
                    Explain the literal meaning of heat capacity so that                         This is followed by
                        students can remember easier.                                             learning about
                    Ask students whether for same amounts of                                     different heat
                        different substances, they have the same                                  capacities between
                        temperature rise for the same heat supplied? Make                         different amounts
                        a guess.                                                                  of the same
                                                                                                  substance.

                                                                                                  *Note:
                                                                                                  Microteaching
                                                                                                  Segment

Lesson                Group students to work in pairs, each student will     1 beaker            Reinforce the
Development 2-         record the temperature of his own beaker of water      containing 400 ml   concept of heat
Reinforcement          or oil.                                                of water            capacity by heating
of heat capacity      Students are to heat 1 beaker of water (400ml) and     1 beaker            different kinds of
and derive its         1 beaker of cooking oil (400ml) using an               containing 400 ml   liquids.
definition.            immersion heater.                                      of cooking oil
                      Using temperature sensors connected to datalogger,     2 100 W             Show the
20 min                 students are to observe the difference in heating      immersion           properties of heat
                       curves. If data loggers are not available, replace     heaters             capacity first
                       with thermometers. Students are to record down the     2 temperature       before introducing
                       temperature every 30 seconds.                          sensors connected   the definition and
                      Remind students to write down the readings in their    to datalogger*      formula.
                       worksheet with the correct units.
                      Show students that for the same amount of heat         Worksheet           Deriving the
                       supplied, the rise in temperature is different.                            definition based on
                      Tell the students they have just observed some         PowerPoint          their observations
                       properties of heat capacity of matter.                 Slides              help them to recall
                      Derive the definition of heat capacity together with                       easier.
                       the students and show the formula. Fill in the
                       definition inside the worksheet: the amount of
                       energy needed to raise the temperature of a            *normal mercury-
                       substance by 1 K.                                      in-glass
                      Together with students, derive the unit for heat       thermometers
                       capacity from the definition.                          may be used if
                      Highlight that the process of heat absorption is       there are
                       reversible – the amount of heat lost during cooling    insufficient data
                       is the same as the amount of heat gained for the       loggers for
                       same change in temperature.                            students.



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Specific Heat Capacity


   Stages                      Activities/Procedures                           Resources      Rationale
Lesson              Ask students to practice doing some questions on        Worksheet     Applying the
Development 3-       the worksheet.                                                        formula to values
Application of      Explain to students that the calorimeter in the         PowerPoint    they recorded
formula              applet, and the beaker in the demo also absorbs         Slides        themselves gives
                     heat. Give them the heat capacity of the calorimeter                  students a greater
10 min               as 53.64J/K.                                            White Board   sense of closeness
                    Ask students to apply the formula to calculate the                    to the lesson.
                     heat capacity of water in the applet.
                    Teacher to walk around helping students who
                     encountered difficulties with their calculations.


Lesson              Explain that since the heat capacity of a substance     Worksheet     Lead students to
Development 3-       is dependent on the amount of substance, it is more                   realize by
Extension of         convenient to consider the heat capacity per unit       PowerPoint    themselves that the
formula to           mass.                                                   Slides        specific heat
specific heat       Ask students to divide the heat capacities of water                   capacity is a
capacity             obtained from the applet and from the demo by its       White Board   constant for the
                     respective masses. Remind students that the density                   same substance.
15 min               of water is 1 g/cm3, so its mass in grams                             Deriving the
                     correspond to its volume in cm3.                                      specific heat
                    Ask them what they observe between the two                            capacity formula
                     values. They should get roughly the same values;                      from heat capacity
                     any variance could be due to experimental errors.                     helps students to
                    From their calculations, explain to students that the                 link concepts
                     heat capacity of 1 g of the same substance (in this                   together.
                     case water) is always the same. This is called its
                     specific heat capacity and they have just calculated
                     the specific heat capacity of water.
                    Define specific heat capacity by extending the heat
                     capacity formula; divide heat capacity by its mass.
                    Remind students that because the specific heat
                     capacity of a substance is a constant, it is more
                     meaningful and it is more commonly used than
                     heat capacity.
                    Ask students to practice some questions on the
                     worksheet. Teacher to go through the thinking
                     process with students, providing guidance and
                     scaffolding.
                    Highlight the differences between heat capacity
                     and specific heat capacity in terms of definition and
                     SI unit.
                    Remind students of the naming conventions: C for
                     heat capacity, c for specific heat capacity.

Lesson              Ask students what applications they can think of        Worksheet     Let students
Development 4        based on the high specific heat capacity of water.      PowerPoint    understand the
Applications        Teacher to lead students where necessary.               Slides        usefulness of heat
                    Some applications:                                                    capacity.
5 min                1. Hot water bottle to keep warm on cold nights.        White Board
                     2. Water used as cooling liquid in car engines
                     3. Land and Sea breezes.

Closure             Remind students of the demonstration done at the        PowerPoint    Provide a summary
                     beginning of the lesson, and ask students to explain    Slides        for the lesson and
5 min                why the balloon does not burst based on what they                     check whether the
                     had learnt on heat capacity: (1) balloon is stretched   White Board   students are able to
                     very thin there is good thermal contact between                       understand the



                                                            6
Specific Heat Capacity


   Stages                      Activities/Procedures                         Resources      Rationale
                     water and flame. (2) due to the high heat capacity                  concept.
                     of water, heat is quickly absorbed and the rubber
                     does not get heated enough to melt.
                    Remind students to realize that water has a high
                     specific heat capacity.
                    Remind students that heat insulators have very high
                     specific heat capacity so they do not get hot easily.
                    Check for understanding by asking students that
                     they have learnt in the lesson.
                    Recap using a concept map.
                    Answer any queries students may have on the
                     topic.
                    Ask students to do some exercises on heat capacity
                     at the end of the worksheet.




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