Investigative study in chemistry by qfK0DH

VIEWS: 9 PAGES: 26

									Investigative study in
      chemistry


                Sophia Cheng
                3 November 2008
        Investigative Study (IS)

   Conducted in groups of 3 to 5 students
   Provide students with opportunities to
    design and conduct an investigation with a
    view to solving a problem
   Students will learn about scientific
    processes and how these processes work
    to generate new information
        Aims of investigative study

   Students can:
       apply their knowledge and understanding of
        chemistry
       develop and apply various practical skills
       develop skills such as creativity, critical
        thinking, communication, problem-solving
       develop understanding on nature of science
    For learning and teaching
     Topic XVI in NSS Chemistry curriculum

    For assessment

                             Practical related task                        Non-practical
                                                                             related task

            Basic Chemical       Experiment           Investigative   Assignment
                Analysis                                  Study

Weighting   20%                  30%                  30%             20%
S5          ≧1                   ≧3                   1               ≧1
S6
Implementation timetable of SBA

 Year of examination   Implementation of SBA

 2012 & 2013           practical related tasks
                       investigative study
                       non-practical related tasks


 2014 and thereafter   practical related tasks
                       investigative study
                       non-practical related tasks
Before/While conducting IS, students
should be guided on:
   How to work together in a group to
    develop an investigation plan and solve a
    problem
   How to define a researchable topic
   How to search for relevant information
    from various sources
   How to write an investigation plan
   How to write a laboratory report or make
    a poster for presentation
         Investigative study (20 hours)
   Design and conduct a first-hand investigation
                  (a) Searching for and      3 hrs
    1. Design
                  defining questions
                  (b) Developing an          4 hrs
                  investigative plan
    2. Process    (c) Conducting the         6 hrs
                  investigation
                  (d) Organizing and         4 hrs
    3. Report     analyzing data
                  (e) Presenting findings    3 hrs
 Using the Allocated Lesson Time (20 hrs)
Sun   Mon    Tue     Wed    Thu     Fri   Sat
       1     2 (a)    3     4 (a)    5     6
  7    8     9 (b)    10   11 (b)   12    13
 14    15   16 (b)   17    18 (c)   19    20
 21    22   23 (c)   24    25 (c)   26    27
 28    29   30 (c)   31
                           1 (c)    2      3
                           /(d)
  4    5     6 (d)    7    8 (d)    9     10
 11    12   13 (e)   14    15 (e)   16    17
 18    19     20     21     22      23    24
     Using post-examination school days
Sun      Mon       Tue     Wed      Thu      Fri     Sat
11        12       13       14       15      16      17
18        19       20       21       22      23      24
25        26       27       28       29      30
July                                                  1
2        3 (a)      4        5      6 (b)     7       8
9        10 (c)   11 (c)   12 (d)    13     14 (e)   15
16        17       18       19       20      21      22
                Implementation schedule
                  Pros                      Cons
Easter, Lunar     -Reserve more time for    -Attendance problem
New Year,         teaching                  -Extra workload
Summer            -Long practical section   -Extent of
holiday…                                    involvement
Post              -Reserve more time for    -Attendance problem
examination       teaching                  -Clash with other
                  -Long practical section   projects of different
                                            subjects


Normal school     -Complement to teaching   -Chopped practical
days              -No attendance problem    sections
                                            -Too hectic
    Try-out: Making Your Own Acid-Base
                 Indicator

Tasks:
  1. Extract coloured pigments from plant
     materials
  2. Use the extract as acid-base indicator
     and find the concentration of alkali in
     oven cleaner
Finding information and planning
Extraction of coloured pigments
Choosing suitable indicators
Choosing suitable indicators
Find the concentration of alkali in oven cleaner
                    More examples
 Salt content of snack




(a)Gravimetric method
(b)Titrimetric methods:
    • Volhard method: back titration of Ag+ with KSCN using Fe2+
        as indicator
    • Mohr method: titration with Ag+ using K2CrO4 as indicator
      Design and make: Chemical cell




“Coin Cell” made by aluminium foil and   This chemical cell consists
coins.                                   of 9 pairs of metal couples.
                                         Its voltage is between 2 –
                                         2.5V.
Self-heating food/drink container
            Getting copper from its ore
                                             CuCO3.Cu(OH)2.H2O(s)
1. To extract copper
   metal from a
   given ore sample                        heat                   H2SO4(aq)

2. To isolate product                CuO(s)                              CuSO4(aq)
3. To calculate
   extraction      C(s), H (g) or Town gas
                               2                          Zn(s) or electrolysis

   efficiency                                          Cu(s)
4. To calculate cost
   of the method
     Appropriateness of the Topic
   Does the activity address something worth
    learning?
   Is the topic socially relevant, interesting or
    motivating?
   Is the cognitive demand appropriate?
   Do students have the required prior
    knowledge and adequate skills?
   Are resources such as journal articles,
    reference books, chemicals and apparatus
    available?
   Is the time available sufficient for the
    activity?
   Are there any safety concerns?
   Can laboratory technicians and others help
    in its implementation?
    Your concern…
   10 groups, 10 different
    projects
   Scale of investigation
   Laboratory safety
   Clash with investigation of
    other science subjects such
    as Physics
   Collaboration with lab tech
    and other teachers
                   Discussion
1.   When is the best time to implement IS?
     Why?
2.   How will you allocate the 20 hours of IS in
     your teaching schedule?
3.   What chemistry investigations do you think
     are suitable for IS?
4.   How much autonomy should students have
     in deciding their research questions?
5.   What guidelines regarding IS will you give
     to students? How will you guide students
     to finish IS on schedule?
6.   How will you prepare yourself to
     implement IS?

								
To top