Case Study: Does my answer look too big (or too small) in this ?

book cover Produced by Graham Currell, University of the West of England, Bristol in association with:
Royal Society of Chemistry, 'Discover Maths for Chemists' website
, and

Essential Mathematics and Statistics for Science, 2nd Edition
   Graham Currell and Antony Dowman, Wiley-Blackwell, 2009

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This new Study Guide is in the process of development - any comments, corrections or suggestions welcome: -


Whenever you perform a calculation in science, you should always check that your final answer is not some ridiculous value. You should not just accept the numbers produced by your calculator without cross-checking that the value is reasonable.

For a example, a calculation which suggests that 1.0 cubic centimetre of sea water contains 3.5 kg of salt is obviously wrong - the mass of 1.0 cubic centimetre of sea water can not be that much more than the mass (1.0 g) of 1.0 cubic centimetre of pure water.

The following short quizzes, of about five questions each, give answers that might be suggested by students for common calculations in science. The aim of each question is to assess whether the magnitude of the answer is about right - you are NOT being asked to re-calculate the exact value for the answer.

Quizzes with video feedback

Example questions
(only 3 questions at present)

Quiz 01 - Moles, concentrations, etc
(Feb 2011 - to be developed)

Useful resources

You might find some of these links useful:

Typical Values

Units in Science

Units of measurement in science (interactive learning resource)
Using SI prefixes, Basic unit conversion, Handling ‘power’ units, Conversion of combined units, Using ‘units’ to understand equations, Examples of using units in science