Why must chemistry students do experimental practical work?

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Why must chemistry students do experimental
practical work?

• To help students learn science acquire and
  develop conceptual and theoretical knowledge.
• To help students learn about science develop an
  understanding of the nature and methods of
  science and an awareness of the complex
  interactions among science, technology, society
  and the environment.
• To enable students to do science engage in and
  develop expertise in scientific inquiry and
  problem-solving.
• (Hodson, 1998, pp. 629-630)

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Cookbook Lab Activities
typical cookbook laboratory activities do not
promote, and often hinder, deep conceptual
understanding they do an extremely poor job of
making apparent and playing off students prior
ideas, engendering deep reflection, and promoting
understanding of complex content. Such activities
mask students underlying beliefs and make
desired learning outcomes difficult to achieve.
Hands-on experiences, by themselves, are
insufficient for coming to an understanding of
the scientific communitys explanation for
natural phenomena students must also be
mentally engaged. . In typical cookbook
laboratory experiences, most all these decisions
are made for students. (Clough, 2002, pp. 86-87)
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Two Ways to Improve the Quality of Lab Activities

• Ask questions at an important step of a procedure
  so that students are given an opportunity to
  consider the rationale for the step.
• Example To determine the heat of combustion of
  a candle.

• There are four levels of scientific inquiry
• confirmation or verification
• structured inquiry
• guided inquiry
• open inquiry

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Guided Inquiry-based Chemistry Experiments

• Are the EMB (2003) exemplars useful? Why?
• Chemical tests for calcium carbonate
• Electrolysis of aqueous copper(II) chloride
• Making sulphur dioxide
• Identification of white solids

• These exemplars are NOT authentic.
• Are they related to the everyday context of
  students?
• Are they relevant to students personal needs and
  curiosity?
• Are they relevant to students future profession?
• Our challenge to increase the degree of
  authenticity

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S4-5 CHEMISTRY
Plan an investigation to compare the effect of
different toothpastes on the rate of tooth decay.
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S4-5 CHEMISTRY
Plan an investigation to determine the amount of
carbon dioxide released by plant debris
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Guided Inquiry-Based Experiment
Design an experiment to determine the density of
the moist gases released by a Redoxon tablet at
room temperature and pressure.
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Formative assessment is essential
..it is not possible to practice inquiry-based
approaches in the classroom without also using
formative assessment practices. (Harlen, 2003, p.
7) This inquiry learning can only take place,
however, if the teacher knows where students are
along the paths toward specific goals. Without
this information, teachers cannot identify the
next steps that students are capable of taking
with understanding. In addition, the more that
students themselves are involved, the more likely
it is they will be able and will want to take
these next steps. These aspects of inquiry have
been identified as formative assessment. (Harlen,
2003, p. 9)
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Plan an investigation to compare the effect of
different toothpastes on the rate of tooth decay.
Design scoring rubrics for assessing students
(1) planning skills, (2) presentation skills, (3)
implementation skills, and (3) written lab
reports.
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What are rubrics?
Rubrics are devices, such as checklists, scales,
or descriptions, that identify the criteria used
to evaluate a students work. Analytic rubrics
Different features or parts of a performance are
assessed separately. Judgments of the quality of
the parts are synthesized or aggregated often
added or averaged to obtain a score or
grade. Holistic rubrics The quality of the
performance as a whole is emphasized rather than
of assessment of its parts.
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How scoring rubrics can be developed to promote
assessment for learning

1. Identify the learning objectives to be assessed.
2. Identify specific observable attributes that you
   want to see (as well as you dont want to see)
   your students demonstrate in their product or
   process.
3. Review literature on assessment criteria. What do
   other rubrics assessing the same skills or
   knowledge look like?
4. Plan and carry out the inquiry-based practical
   work yourself. Then make a list of the important
   assessment criteria based on your experience.
5. Collect student work and sort it into groups by
   quality. Write down the important features that
   make the groups different.

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How scoring rubrics can be developed to promote
assessment for learning

1. Design analytic scoring system to enhance student
   learning. Check content, construct and/or
   criterion validity. Reduce unreliability by
   defining scoring categories clearly.
2. Include features to develop students
   metacognitive skills.
3. Try to assess student work using your rubric.
   Then fine-turn the wording based on the first
   trial.
4. Collect samples of student work to serve as
   anchor papers.