When the 7.30am call comes and I say yes to a day of “general supply”, I’m rolling the dice. I never know if I’ll be teaching quadratic equations, the rise of fascism in 1930s Europe, or how to set a blancmange. One of the things I like about supply is getting to “have a go” at all the other subjects. It feels like a missed opportunity that schools don’t get their staff to spend more time in each other’s lessons. Most teachers will probably go their whole career without seeing a lesson taught outside their own faculty.

And I can tell you from bitter experience, aside from the obvious differences with the content, that not all lessons are equal. Here then, is why supply teachers look forward to some lessons more than others.

The worst lessons

Maths

I’m sure part of the problem here is that I’m not a maths specialist. Like too many people, when I learned maths at school it not only baffled but really irritated me. Why the hell did I need to know that the square of the hypotenuse was equal to the sum of the square on the other two sides?

Maths always felt like someone talking to me in a language that I not only didn’t understand, but that I suspected wasn’t even a language at all, just a bunch of random symbols someone had made up for a joke. If the students in a maths cover can’t do the work, there’s very little scope for trying to battle through it. The fallback empathy writing task, along the lines of “imagine you’re an escaped slave/Jane Eyre/living in an earthquake zone etc” isn’t much use here either. “Write a diary entry for a day in the life of a negative integer” is a tough sell.

PE or dance

Thankfully I haven’t had to do these too often, because boy, are they hard work. I had an hour of PE with a Year 2 class once and it nearly killed me. It isn’t a question of poor behaviour, it’s more that some kids just really embrace the opportunity for untrammelled physical activity.

I’ve long believed that being made to sit still at a desk for hours is not a natural state for the adolescent. No clearer proof of this can be seen than when they’re freed from the shackles of the classroom and sent outside. It’s like opening the doors of Primark on the first day of the January sales. I’m always on edge that someone’s going to end up in hospital, and then I’m never going to get away by 10 past three.

PSHE

I used to run a PSHE department and I genuinely believe it contains some of the most important information kids need, but honestly, what a nightmare to teach. The problem is that the students know there’s no exam and so for the most part they can’t be bothered. And who can blame them? When we construct a system where success and status is based primarily on test scores and target grades it’s hard to see why they should expend valuable mental energy in a subject where all you get is a smiley face sticker telling you you’re a good citizen. If I get a PSHE lesson I use it as an opportunity to learn all the latest drug slang.

The best lessons

Science

This is partly down to the health and safety issues and partly down to the fact that science teachers tend to be a rum lot. In science lessons kids sit still and do what they’re told. And the science department always set lots of cover work. It must be the third law of thermo-gravitational covalence or something (OK, I’m clearly not a science specialist).

Art

Where the science department tends towards the structured, efficient and disciplined, most art departments are a little more free-thinking and fluid in their approach to learning.

Why? I think because most art teachers are totally cool and don’t give a crap. I don’t mean about the students, but about “the man”. Most are secretly trying to tear down the system from within. And because the teachers are relaxed, the kids are relaxed too; it’s as though everyone lets out a collective sigh of relief as they enter the art room. The work’s usually unstructured too: “Sir, I wasn’t really feeling the work you set, so instead I’ve made a sculpture out of ripped up science textbooks and yoghurt pots that represents the suffering of the street children in Venezuela. I’m sure Miss wouldn’t mind.”  And if Miss doesn’t mind, then neither do I. Pass the powder paints, I think I’ll have a go myself.

The writer has recently taken up supply teaching after 20 years in a full-time teaching job