Assessment of Students’ Written Work

Each group of students should normally present a written report of their experiment to the teacher within a few days of doing the experiment.

If the teacher has performed the experiment in advance, marking the 8 to 10 scripts is a quick process, particularly if students are encouraged to write down only those things required by the experiment instructions, numbering their answers accordingly (This provides some training in exam technique).

Although each teacher will have their own preferences, the following is a list of points to look for when marking students’ work:

• Readings: Properly tabulated; units in headings; heading names; appropriate accuracy; repeated & averaged where necessary; accurate calculation and labeling of new quantities (e.g. \(\sin x\) etc.).
• Graph: Title; scales chosen to spread points diagonally right across the paper if possible; axes labels (quantity, unit, scale factor, numbers); points (accurately plotted, small o-dot preferred \(\odot\), not \(\otimes\), etc.); smooth best-fit curve drawn (not a polygon); overall neatness (lines thin, in pencil).
• Gradient: Two points chosen and clearly marked (wide apart), or a tangent accurately passing through one point (line should be long).
• Y-intercept (if required): Point clearly marked; must lie on paper!
• Working: Algebra clearly laid out showing steps logically; correct substitution; (arithmetic details need not be shown); answer to sensible number of signigicant figures (3 normally suitable); number in scientific notation (\(1.3 \times 10^{-6} \text{A}\), or \(1.3\mu\text{A}\), not \(0.0000013\text{A}\)).

Generally if an answer to a question is not of a sensible size, the student should be aware of it and comment accordingly (e.g. if unknown mass = \(3 \times 10^{18}\text{kg}\)!). The student could then be given full credit for correct working based on inaccurate data.

In the exam practicals, the marks shown for each question are for guidance only, and should not be taken to necessarily be the same as the exam authority originally allocated.

Answer keys are not provided as in many cases the answers obtained depend on the particular apparatus or samples used. Be cautious with any answer key or sample results that you develop. These are experiments where observation, hypothesis, testing, and questioning are the objectives – allow students to think it out for themselves!