Sometimes when I’m covering a class, because the regular teacher is on a training course, or taking a group to visit the Science Museum, or lying at home under the duvet with a bottle of whisky and a Netflix box set, things actually run smoothly.

From time to time, the work that’s been set makes sense, and the students aren’t all disturbed lunatics, and everyone just gets on with things. And I get to sit at the front of the class and take it easy. 

On these rare occasions, dare I say it, things can sometimes get a little boring. At least things would get boring, if I wasn’t invariably surrounded by interesting new stuff to learn.

On days like these, I’ve used the opportunity to catch up on some of the subjects I never quite got on with when I was on the other side of the teacher’s desk. 

Reading the textbooks

Take science, for example. I’m a little ashamed to admit that pretty much the whole of science passed me by at school. I blame the teachers of course. I was taught by a series of freaks and oddballs who put me off the whole subject. 

These days, I often find myself covering science lessons, and I usually feel out of my depth. Consequently, I’ve tried to catch up by reading the textbooks and even having a crack at the work set for the kids. 

The problem is that everything you read in the books always assumes some prior knowledge, which I just don’t have. I’ve been working my way up from Year 7. 

Luckily, science cover lessons tend to be very well planned, so it’s enabled me to get a fair bit of reading done. I was extremely proud of myself when just last week I managed to spend an hour working out how to balance chemical equations with a Year 9 class. I don’t know who was more pleased when we got it right, them or me. OK, it was definitely me.

The existence of God

RE is another subject where it would be fair to say I didn’t excel at school. These days, I find trying to get my head around such complicated ideas as Aquinas’s challenge to the teleological argument for the existence of God genuinely fascinating. (I’m sure all we did when I was at school was learn quotes from the Gospels.) 

It’s been a little harder to catch up here, as in contrast to science covers, RE classes are often total chaos. I’m not entirely sure why, but let’s just say the typical RE teacher tends to have a different standing in the school community compared with the teachers in the science department. 

As I tend to get less time to just sit and read the textbooks in these lessons, I get the students to teach me instead. I tried to get one table to explain the concept of the Holy Trinity recently. 

They did fine with the Father and the Son, but found the idea of the Holy Spirit a bit trickier. We checked the textbook, but it honestly wasn’t much help. In the end, we decided to settle on the part that suggested God was an idea so extraordinary that man couldn’t hope to understand, which seemed like a bit of a cop out to me, but they all merrily copied it down and considered it job done. 

I wasn’t sure I was much clearer on the subject, although in the next chapter I did learn that, according to Islam, man is made of clay and Jinn are made of smokeless fire. Who knew?

Survival of the human race

Geography falls into the same category with regard to my own lack of knowledge. Once again I blame my teachers - if I tell you that my geography teacher for the first few years of secondary school was nicknamed “Hitler”, you’ll get the idea. 

This is really a shame, because it’s turned out that all the stuff geography teachers were banging on about 30 years ago is really, really important and quite possibly crucial to the continued survival of the human race. Although all I recall learning about was coastal erosion and how an oxbow lake was formed. 

These days, I’m fascinated by geography, if rather ignorant, so I tend to steer any geography cover lessons around to discussions about climate change. I make sure we all praise the kids who walk to school and don’t eat beef, while pouring scorn on the ones with single-use plastic bottles on their desks. We’ve all got to do our bit, after all.

A word of caution if you ever find yourself in the same position: I’ve occasionally got so caught up reading a textbook on one of the subjects I ditched during my own school days that I’ve looked up 20 minutes later to find that the class has descended into total mayhem. 

“What are you all doing?” I’ll shout, “This stuff’s really interesting!” Honestly, education’s wasted on kids.

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