Roche Limit

Essential, foundational ideas of physics are being presented to children by teachers who know nothing about them themselves. Able children are being undermined by the belief that there is nothing in the compulsory science curriculum that cannot be taught by any science teacher and that physics teachers, bringing only enthusiasm to an inherently dull subject, are therefore not required for physics lessons.

Having just finished a unit on forces and motion with 16- and 17-year-olds, we started on work and energy. After some introductory discussions and activities, the students were given a task to research and describe how wind turbines worked, in preparation for a study of the work done by the wind. Prompted to describe how the wind makes the generator turn, each student wrote that the wind's energy did it. When pressed, one offered that the wind's kinetic energy spun the blades and the blades' kinetic energy was turned into electricity. How does kinetic energy do that then? Well, the generator turns kinetic into electricity, they said, something to do with magnets.

Well, that's just dandy, as it is really no more than a plausible sounding 'just so' story. Without the technical terms the explanation is empty. “The wind turbine has something about it that makes electricity from wind” has nothing of substance and only a patina of education. The answers are routinely consistent with the idea that energy is a sort of fluid with some physical reality, akin to the caloric whose existence was disproved when Joule showed that heat was a method of energy transfer.

So how do bright pupils routinely get through secondary school physics lessons without a working understanding of the relationship between work and energy?

The short answer is: biology teachers.

Well, not their existence per se, but their willingness to teach physics topics about which they know nothing. That, and the connivance of school managers and government ministers who pretend that every biologist, chemist, environmental scientist, biochemist, physicist, engineer, geologist, metallurgist and zoologist can be treated as a generic science teacher, and should be able to teach any science specialism to any class up to age sixteen.

Of course, that is a self-serving cynical delusion. Cynical, because having that belief allows a head teacher to claim that their school has no vacancies, even when, as is the case with at least one school that feeds to my sixth form, they have had no physics teacher for several years. That school even takes the brightest pupils and teaches them more than the minimalist physics in the 'double science' GCSE, dragging them through separate biology, chemistry and physics courses without even bothering to employ a specialist physics teacher.

But does it matter? Can't a graduate scientist teach any of the simple topics that appear in the secondary curriculum, as long as they refrain from teaching A levels?

The response must be a clear 'no'. It should be shouted from the rooftops and at all education ministers, head teachers and science department heads. Specialist science teachers are not interchangeable. Biologists, especially, do not understand physics. They are often required to teach Newton’s Laws of Motion and Energy to the younger secondary pupils, but I have yet to meet a biology teacher who understands them even in the shallowest terms.

Asked about his willingness to teach from a position of ignorance, a biologist Head of Science shrugged it off with a “Well, that’s physics”, while more recently qualified teachers say they think that they teach physics better than the specialists as their difficulties with it themselves puts them closer to the children’s’ experiences. Honestly! I have heard both comments several times.

Secondary schools in inner-city areas, schools without sixth-forms and those whose managers insist on making physics teachers teach biology and the biology teachers physics, will continue to lose physics teachers, and pupils will fail to see the wonder and coherence of physics.

(originally written 2008)