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Outcome 2

Written and/or oral recorded evidence for outcome 2 should be assessed by the production of two full laboratory reports. The laboratory reports must cover two of the following science disciplines: biology, chemistry or physics.

The laboratory reports must contain the following:

Exemplar laboratory reports are available on the Understanding Standards website via the links provided below.

A guidance document for learners on laboratory reports, including an exemplar report which may be issued to them, (Link 8: Laboratory report guidance for learners) is available on the Understanding Standards website via the link provided.

An assessor checklist for marking laboratory reports (Link 9: Laboratory report assessor checklist) is available on the Understanding Standards website via the link provided.

A learner’s response will be judged satisfactory where the evidence shows that the learner can achieve the evidence requirements shown below to the standard exemplified in the commentary.

Evidence Requirements

Commentary

Assess the reliability of results correctly with respect to the degree of accuracy of the procedure.

 

Learners are required to assess the reliability of the results in both laboratory reports. The approach taken will depend on the nature of the experiment. Learner statements must be justifiable in terms of the practical activity and the underpinning science. Statements such as ‘sample may have gone off ’ or ‘human error’ are not acceptable.

Where appropriate, learners should make reference to theoretical, literature or manufacturers values.

One aspect that may be considered for volumetric chemistry experiments is the tolerances of analytical glassware. An information document on tolerances, which may be issued to learners, (Link 10: Uncertainties in glassware) is available on the Understanding Standards website via the link provided.

It should be noted that experimental results must meet an acceptable level of accuracy. The fact that learners are required to assess the reliability of results does not negate this. Large divergence from theoretical values will indicate that either the learner’s performance of the practical activity was faulty or that there were significant shortcomings in the experiment design, equipment or materials. What constitutes an acceptable level of accuracy will vary according to the nature of the experiment, but as a guideline an outcome within 10% of the theoretical value could be expected.

Where appropriate, an experiment should involve replicate readings to help ensure accuracy and reliability. The replicate readings must show an acceptable range of concordance (eg for titrations with standard 50ml burette, titres should be concordant to 0.2ml, ie all accurate titres should fall within a 0.2ml range of each other).

Present observations/measurements in an appropriate format for the results, which on a minimum of one occasion should entail use of a graphical method.

The learner must select the most appropriate way of presenting information graphically which may be in the form of a graph, bar chart or histogram.

Learners should produce a graph from their experimental data. The graph may either be hand drawn or generated using an IT package. Guidance on graph requirements (Link 11: Graph requirements) is available on the Understanding Standards website via the link provided.
 

Analyse and interpret results correctly from the presented information. The learner must be able to interpret when presented with information in a number of related but straightforward forms.

  

Learners should correctly analyse and interpret data from their experiments. What is required will depend on the nature of the experiment, but could involve identifying trends, comparing to expected values or to hypothesis.
 

Perform calculations from measurements correctly. Learners are required on at least one occasion to perform calculations which involve at least three different steps and require either the use of mathematical equations or the handling of statistical data.

  

The calculation should involve three mathematical steps. Simple manipulation of raw data, eg rounding, averaging and subtracting initial readings from final readings do not constitute steps of appropriate level.

Examples of suitable 3-step calculations could be determination of mass % ethanoic acid in vinegar, determination of percentage yield or determining the percentage loss of momentum in an air track collision.