Resource Database: Geography, Earth and Environmental Sciences

Title Using Home-made Software to Illustrate Difficult Concepts
Originator Mike Tullett
Department School of Environmental Sciences, University of Ulster at Coleraine, Cromore Road, Coleraine, BT52 1SA, UK
Tel. +44 (0)28 70 324689
Fax +44 (0)28 70 324911

Mike Tullett, in the School of Environmental Studies at the University of Ulster, has been using some simple, home-grown computer programs (in BASIC) to teach elements of physical geography for the past eight years. His programs model the geostrophic and gradient winds, wave height, duration and time period. The students can enter any pressure gradient at any latitude and run them until they get bored! Other programs model reflection from plane water, the sun's daily path across the sky at any latitude/longitude and date, and there is also one that calculates humidity.

The programs described

For the wind programs, students enter the isobaric interval in millibars, then the isobaric spacing in kilometres and, if they are dealing with a cyclone or anticyclone, the radius of curvature. If they enter impossible atmospheric variables then the program prompts them to be more sensible. Results are largely numeric, though one program gives a graphical plot of geostrophic wind speed against latitude for the same pressure gradient.

The waves programs, which model both shallow and deep water waves, require students to enter a wind speed in m/s, a fetch in kilometres and the duration of the wind blowing in hours. The output includes the significant wave height in metres, wave length in metres and wave period in seconds. Students are asked to keep two of these constant and vary the third, and to do this for all three variables. They are thus able to see that all three have limits beyond which the waves would not grow. By running the program many times they are able to produce their own graphs, say wind speed versus wave height with constant fetch and duration.

The sun program produces graphical output. Students enter day, month, latitude and distance from nearest time meridian (in degrees W or E), and the program plots the sun's elevation on the vertical axis of a graph against clock time on the horizontal axis. (The 'equation of time' is built into the program.) Students are always fascinated when the program is run for the north pole in summer. Very few have ever realised that the sun just seems to encircle the sky at the same elevation over 24 hours, and their concept of time, based on noon being when the sun is due south and at its highest point in the sky, breaks down near the poles.


Although the original idea was to put personal programming skills to some use in teaching difficult topics, there was also the educational problem that putting formulae on the board without the students ever putting them into practice produced limited understanding. In the 'good old days', students would be asked to do a hand calculation, but this was out of the question with the wave programs, because they involved hyperbolic functions.

Another fundamental problem is that the mathematics ability of the introductory groups of students is usually very limited, and their background in physics is even weaker. These weaknesses can usually be traced back to the school syllabus.


Students say they have found the programs useful in helping them to understand some very tricky concepts, wind modelling in particular. An assessed exercise has now been based around the use of these programs, in which students have to present their numeric answers and also a short written section with graphs to summarise their findings and demonstrate their understanding of the concepts.

Mike's experience stands in clear contrast to the increasingly common use of Windows-based, multimedia-style courseware, which is costly to produce and does not necessarily produce greater educational benefits than simpler computational programs. The cost of producing the software has been very low, except for the time needed to learn how to program, back in the late 1980s. However, a recent twist in this tale is that the acquisition of new computers now makes it necessary to rewrite the software for the Windows environment.


Home made software
Sun program
Wave program
Wind program

This is one of the case studies which appears in the GDN Guide "Teaching and Learning Geography with Information and Communication Technologies"

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