What’s the difference between a calculator and a computer? One answer might be that this government seems to loathe the former and love the latter. But although there are obvious differences in size, price, display and so on, at the heart of the calculator lies a microprocessor.

The development of the graphic calculator nearly 15 years ago was a major breakthrough, bringing a large amount of memory, alphabetic characters on the keypad, and a programming language. Since then technological advances have been mainly in software, making the calculator more powerful and easier to use.

On the hardware side, the most significant developments have been an improvement in communication between devices and greater compatibility with other types of machines. Most graphic calculators now have a connecting socket and lead, and software and cables for connecting to PCs and Apple Macintoshes. There are models which can connect to a large liquid crystal display pad for whole-class projection with an ordinary OHP. Compatible hardware includes data-loggers and probes with names like CBL (Calculator Based Laboratory) and CBR (Calculator Based Ranger).

This year the Department for Education’s mathematics curriculum IT support group has funded a National Council for Educational Technology project investigating the use of such equipment at key stages 3 and 4 in maths, science, geography, design and technology, PE, and even personal and social education.

Maths and science staff have collaborated, for example, in activities looking at distance-time graphs, velocity and acceleration. Each of the four schools received a “teacher’s kit” consisting of a TI-83 graphic calculator, an OHP display pad, a CBR “motion detector” and a computer link (total cost around pound;250). The schools also had pupils’ TI-82 or TI-83 calculators at around pound;55 each, as well as CBRs (pound;70) and CBLs (pound;160). All the equipment is battery-driven and portable, so the CBRs, for example, could be used on the running track in PE. Maths students at one of the project schools, Admiral Lord Nelson in Portsmouth, experimented with the equipment as part of a health and fitness study. They used the CBLs with simple heart-rate monitors (light sensors clipped to the earlobe) to monitor heart-rates before and after exercise.

Two of the teachers had multimedia laptops as part of the project, and all participating schools were able to share materials and ideas by e-mail, and access software via the Internet.

The British Educational and Communications Technology Agency (BECTA, as the NCET is now known) will shortly be publishing a book based on this mini project, which will be free to schools, and also available through BECTA’s Web site.

So calculator technology has already gone a long way to becoming a cost-effective tool to complement the more common educational ICT products. But recent developments have taken this a big step further. One of these is the arrival of “Flash Rom”. It is a “non-volatile” form of memory, like Rom and unlike Ram, which means that it does not require power to retain its contents. Second, unlike Rom and more like Ram, it is “many times rewritable” - where “many” may be 10,000 to 100,000 times. It is extensively used in computer modems and digital cameras, and the price has fallen to the point where it increases only slightly the cost of a calculator. It effectively becomes the “hard disk”, which turns a graphic calculator into a small laptop. It allows manufacturers to provide software “fixes” for any known problems, and to sell upgrades and special application software - either on disk or through the Internet.

More interestingly, it lets you collect programs to support specific aspects of the curriculum. Many of the programs that were around in the days of the BBC micro and the 380Z could easily be adapted for the new generation of Flash-based graphic calculators.

Texas Instruments has just unveiled two new calculators, the TI-89 and TI-73. The former is a mathematical thoroughbred, suitable for GCSE, A-level and university, which can also perform symbolic manipulation. It will cost around pound;100. The latter is aimed at what the US calls “middle schools”, which is roughly equivalent to key stages 2 and 3. It has a good range of data-display and manipulations, as well as fractions. It will cost around pound;60.

So a school could buy a class set of 15 TI-73, a teacher’s OHP display model, a CBL, a CBR and a computer link for around pound;1,250 - about the price of a single PC. In mathematics, groups such as the Association of Teachers of Mathematics and the Mathematical Association, or the Teacher Training Agency, or BECTA might produce packs of software to support particular aspects of the subject - such as space, shape and measure - which could be downloaded at little or no charge from the relevant Web site.

The Dearing review recommends that students in higher education should provide their own computing equipment in two to three years’ time. A requirement to provide a laptop computer costing around pound;1,000 could deter even more students from taking courses in mathematics, the sciences and engineering. An alternative scenario is that a faculty might lend or lease students TI-89 calculators at a tenth of the cost.

Also under development are class networks which can link graphic calculators, compatible data-loggers, other hand-held devices and conventional personal computers so that the calculator and computer-based ICT products can co-operate, not compete.

Adrian Oldknow is chair of the DFEE’s maths curriculum IT support group.