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)

…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 community’s 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)

Cookbook Lab Activities

Two Ways to Improve the Quality of Lab Activities

(1) 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.

(2) There are four levels of scientific inquiry:

• confirmation or verification

• structured inquiry

• guided inquiry

• open inquiry

Are the EDB (2003) exemplars useful? Why?

1. Chemical tests for calcium carbonate

2. Electrolysis of aqueous copper(II) chloride

3. Making sulphur dioxide

4. Identification of white solids

Guided Inquiry-based Chemistry Experiments

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

Plan an investigation to compare the effect of different toothpastes on the rate of tooth decay.

S4-5 CHEMISTRY

Plan an investigation to determine the amount of carbon dioxide released by plant debris

S4-5 CHEMISTRY

Design an experiment to determine the density of the moist gases released by a Redoxon tablet at room temperature and pressure.

Guided Inquiry-Based Experiment

…..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)

Formative assessment is essential

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.

Rubrics are devices, such as checklists, scales, or descriptions, that identify the criteria used to evaluate a student’s 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.

What are rubrics?

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 don’t 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.

How scoring rubrics can be developed to promote assessment for learning

6. Design analytic scoring system to enhance student learning. Check content, construct and/or criterion validity. Reduce unreliability by defining scoring categories clearly.

7. Include features to develop students’ metacognitive skills.

8. Try to assess student work using your rubric. Then fine-turn the wording based on the first trial.

9. Collect samples of student work to serve as anchor papers.