About 50 per cent of all Leaving Certificate students will take the biology examination today. Only about 14 per cent of all students will take the physics examination next Monday, and a mere 11 per cent will take chemistry next Tuesday.

The proportion of students taking biology has remained pretty steady over the past 15 years, but the proportion taking physics has markedly declined, from 20 per cent in 1986; some 21 per cent of students took chemistry in that year.

I will discuss the declining interest in physics and chemistry, but first I will consider the educational quality of the curricula in biology, physics and chemistry.

We can reasonably expect three things from the science curriculum. It should (a) provide a grounding in the basic principles, (b) provide a platform on which further study can build and (c) stimulate interest in science. The existing curriculum basically satisfies the first two criteria but leaves something to be desired under criterion (c).

However, new curricula in chemistry and physics will be introduced in September 2000 and a new curriculum in biology will begin in September 2001. These new courses make special efforts to stimulate the students' interest in science.

Biology, physics and chemistry are laboratory sciences, i.e. you must work with your hands as well as your head. Practical work is not sufficiently emphasised in the existing curricula and there are no formal practical examinations. The new curricula place special emphasis on practical work. The new curricula each specify about 25 mandatory experiments and, overall, about 20 per cent of the time will be spent on practical work.

Laboratory classes teach practical skills and illustrate theory through practice. The practical topics are selected with an eye to forging a connection with the familiar world. For example, the new chemistry practicals will include experiments on measuring the hardness of water, measuring the iron content of an iron tablet, etc.

Practical classes are an excellent way to stimulate interest and are also an excellent teaching tool in themselves. As the old Chinese saying puts it: "I hear and I forget, I see and I remember, I do and I understand." It is hoped that practical examinations will be introduced, and this certainly should be done - otherwise the practical classes will not be taken sufficiently seriously.

The theory content in the existing curricula is worthy but needs updating and also it could be more generally stimulating. For example, many would feel that the biology curriculum over-emphasises the classification of organisms and that, in chemistry, the organic curriculum is po-faced and unstimulating. The new biology curriculum accommodates to the changing face of modern biology by including more biochemistry.

The new chemistry curriculum has new sections on natural product chemistry, environmental chemistry and industrial case studies. The new physics curriculum has an exciting new treatment of particle physics, and both physics and chemistry include a new topic called "science, technology and society". The new curricula will also call for a somewhat different style of teaching. For example, the teacher will supplement a description of a scientific principle with interesting details on the life and times of the scientist who discovered the principle. Faraday's Laws will be accompanied by the story of how Michael Faraday (1791-1867) transformed himself from a bookbinder into one of the greatest-ever scientists.

The existing and the new curricula provide a suitable preparation for the study of science at third level. But many people don't realise that it is quite feasible to study biology, chemistry or physics at third level without having taken them at second level. These subjects start off from first principles at third level. It is true that, if you haven't taken science before, you will have to work harder in first year at university; but, on the other hand, you will not be bored by going over familiar territory.

In my opinion, the main reasons for the declining interest in physics and chemistry are, in order of importance, (1) the general perception that jobs in laboratory science are relatively scarce and are very modestly paid; (2) these subjects are perceived to be difficult compared with biology; (3) these subjects are perceived to be dry and specialised.

I will deal with reason number 3 first. Many students are intuitively attracted more to biology than to the other two subjects. Biology is the study of life, and we feel that studying Biology can tell us much about our own bodies, our own health, etc. Physics and chemistry don't make the same general personal appeal. However, this is only a marginal thing - many students are deeply drawn to these two fundamental sciences. Reason number 3 makes only a minor contribution to the current wide gulf between uptake of biology and uptakes of physics and chemistry.

The main explanation for the decline in interest in physics and chemistry, I believe, is reason 1, closely followed by reason 2. I will deal with reason number 2 first. Physics and chemistry are perceived by students as more difficult than biology and therefore less likely to score those elusive As and Bs. As we all know, the points system is a powerful animal - a different kind of a Celtic Tiger. Student interest in Japanese embroidery would take off if it was available as a subject option and was perceived to be an easy B.

In my opinion the most powerful force acting against physics and chemistry is the materialistic climate of the times. Most students seem primarily interested in careers that are perceived to be plentifully available and to yield big bucks fast. The perception is that such careers reside mainly in the computer/information technology (IT) sectors and students are flooding into these areas at third level.

Computer science and other IT subjects are intrinsically rigorous and quantitative, requiring a good facility with mathematics - the very qualities that we fear turn many students off chemistry and physics. But in this case the lure of the well-paid job overcomes all obstacles.

The new curricula in physics and chemistry should make these subjects more attractive to second-level students and should ensure that the achievement of good grades is tightly coupled to the extent of student effort.

But the most decisive move that can be made to improve uptake of physics and chemistry is for industry to broadcast aggressively that jobs are available for graduates in these subjects and to ensure that they are paid at highly competitive rates. Otherwise we may soon face a strangling shortage of chemists, physicists and engineers - in other words, most of the people primarily responsible for producing existing products and developing new products.

William Reville is a senior lecturer in biochemistry and director of electron microscopy at University College Cork.