The rule of three is a well-known writing principle. It’s a satisfying number. Imagine a joke where only two people went into a bar ─ it just doesn’t have the same ring. In physics we have Newton’s three laws of motion; music has musical triads; Christianity has the holy trinity, and who could forget Tony Blair’s “education, education, education”?

And in school we have the “three sciences” - an arrangement that I have come to believe is one exception to the rule of three.

Biology, chemistry and physics have not always been seen as the main areas of science. It wasn’t until the 1950s that these traditional three subjects took hold, and even then the arrangement was more a consequence of the exam system than a deliberate curriculum decision.

Our secondary science teaching is being hampered by this outdated and ideological ménage à trois. There are at least five core science disciplines, including Earth sciences and astronomy as well as biology, chemistry and physics.

Not only does the current arrangement leave gaps in the curriculum, it means that schools can face difficulty in recruiting specialist teachers. And when schools do manage to recruit specialists, they force them to become generalists. Many physics teachers don’t like teaching biology, and vice versa. Despite this, our school curriculum and timetabling often requires science teachers to deliver all the disciplines to at least the end of key stage three.

No ‘pure’ science

We need to be more honest about what science really is. We labour under the mistaken idea that somehow the sciences all work in the same way and can be taught by anyone with any science degree. However, the differences in subject matter are quite stark - imagine asking every history teacher to teach geography and religious studies along with history as “the three humanities”. That’s the scale of the challenge regularly taken up by science teachers.

We need to reimagine the science curriculum and break down the rigid boundaries of the existing trivium. In doing so, we could bring together natural partners. Doesn’t it make more sense to group physics and astronomy with mathematics? Why not put biology and environmental science together, or chemistry and the earth sciences?

A more flexible approach could widen the field of potential specialist teachers to include those studying degrees in astrophysics or engineering and would also more closely resemble the faculty arrangements found in universities. University students will rarely do a “pure” degree in biology, chemistry or physics, so why do we persist in teaching this way in schools?

It’s time to abandon the “three sciences”. We need to deliver a more coherent science education that meets the needs of children today, rather than turning back the clock to a supposed “golden era” which bears no relation to real world science.

James Williams @edujdw is a lecturer in education at the University of Sussex School of Education and Social Work.  

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