Cambridge International AS and A Level Marine Science Practical Skills 3: Recording observations and raw data

Study guideUpdated 16 Oct 2026

Cambridge Marine Science 9693 practical notes on raw-data tables, observation language, biological drawings, labels, scale, magnification and traceable records.

Recording Observations and Raw Data reviews tables, biological drawings, labels, annotations, magnification and scale for Marine Science practical study. Check the current official syllabus and question instructions for the assessed scope. A scientific record preserves what was observed before interpretation changes it.

A Cambridge Marine Science evidence-recording workflow linking raw measurement, observation, table structure, biological drawing, scale and later processing

Practical recording conventions

Use enough space, organise related results coherently, distinguish raw, calculated and deduction fields when needed, place units in descriptive headings and record decimal places appropriate to the measurement. Follow any table format specified by the question.

A useful convention for observation drawings is a large, unshaded pencil drawing with fine, clear outlines and straight label lines without arrowheads. Follow the question and course instructions for the required drawing format.

Practise drawing at a specified magnification, adding an appropriate scale line and calculating image or drawing magnification for both familiar and unfamiliar structures. The current syllabus and question instructions govern assessment requirements.

Raw data, processed data and deductions

Raw data are direct readings or observations before calculation. Examples include each quadrat count, initial and final shell mass, oxygen concentration at every time, or a recorded colour change.

Processed data are derived from raw values, such as mass loss, mean abundance, rate, percentage change or diversity index. A deduction is an interpretation based on evidence, such as identifying an ion, structure or taxonomic group.

Keep these stages distinguishable. Recording only a mean destroys the replicate values needed to inspect spread or recalculate the result.

A correction should remain traceable. In handwritten work, cross out a wrong entry once and write the replacement clearly rather than erasing the history into ambiguity.

One coherent results table

Use one coherent table when related results can be presented clearly together. Linked tables may be appropriate for different data structures or when the question requires them. Put the independent variable or sample identifier in the first column, followed by raw replicates, processed values and deductions.

Use a title or surrounding sentence to identify the investigation. Column headings should describe the quantity, not merely "result" or "reading".

A logical shell investigation structure is:

  • pH
  • initial shell mass for each replicate
  • final shell mass for each replicate

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Sources

  1. Cambridge International AS and A Level Marine Science 9693 syllabus for 2028-2030