Orders of Magnitude

Students will be expected to make order of magnitude calculations. For example, in cell biology, students will need to demonstrate an understanding of size and scale. When looking at topics on the atmosphere, pollution and climate change, students should be able to use orders of magnitude to evaluate the significance of data. An understanding of orders of magnitude is also expected when looking at road safety and stopping distances for example. In some cases as part of the physics course, students will be expected to be able to give estimated values of particular quantities such as typical speed for wind, the speed of sound and various transportation methods (e.g. walking and cycling).

The biggest challenge in this area of mathematics when used in the science classroom is the basic difference between mathematics as an abstract subject and its use as a tool for science. Mathematicians are quite happy to talk about exact numbers however big or small, but in science a measurement stated as part of the results of a scientific experiment can NEVER be exact.

Students are often insecure or lack confidence in making their own decisions about what accuracy to use and when. Use a range of scientific contexts to give them opportunity to explain and justify their choices. Students are often more likely to trust the output of a calculator, even if the sum has been entered incorrectly, than to ask whether it is reasonable based on the context and their estimate.

Practice with the use of numbers is a crucial scientific skill. This list of interesting questions will allow students to practice these skills whilst developing awareness of orders of magnitude in scientific contexts.

These resources help prepare students for this by reviewing place value when multiplying and dividing by 10 and the use of powers of 10 in scientific contexts. It then goes on to suggest some areas for investigation focusing on climate change.

You may find this orders of magnitude and standard units table helpful.