Do you know the periodic table? Or at least what the periodic table is? Distinguished chemist Dr Peter Rook knows it off by heart - and it’s his life’s work to explore its mysteries. This funny, quietly touching show - staged as a mock lecture, but in truth an accomplished piece of theatre - sees the likeable middle-aged scientist explore a chemical conundrum, and the even-greater riddle of how to find happiness. Pay attention at the start. There will be a test later on.

There’s a lot of science in this show. Not a clichéd arty take on science, but the real thing: the scientific method, with its hypotheses and experiments, and its ceaseless quest for knowledge. Don’t be put off if that’s not your background, because the story is really about a character, and that character is accessible to everyone. But if you do count yourself a scientist, you’ll find there are plenty of crafty in-jokes and - much more importantly - resonant themes to enjoy.

The character, Dr Rook, warns us at the start that he’s bad at jokes; and true enough, he’s come prepped with a large number of terrible chemistry puns. (Too many, perhaps. There were moments in the early part of the script when I longed for him just to crack on.) But the actor, Martin Stewart, is a master of quiet comedy, with a momentary pause or meaningful glance often enough to highlight a mischievous thought or line. He makes Dr Rook a lovable personality too, enthusiastic and rumpled and very slightly vulnerable: the sort of man who can ask his audience, “can I get a ‘woo’?”, and receive an unhesitating and whole-hearted reply.

But Stewart delivers intensity when it’s needed as well, making one creepy scene in a university laboratory crackle with uncertainty and suspense. When he describes the dreaming spires of Oxford, it’s evocative enough to all but conjure them onto the stage. And there are some more adventurous shifts in tone: a much-telegraphed physical-theatre interlude is on the face of it a joke, but on a deeper level perfectly matches the doctor’s frenetic mood, as he’s confronted with evidence of a scientific impossibility and his whole belief system implodes.

The ending, for me, has the slightest tinge of a missed opportunity. Our protagonist does have a satisfying epiphany, but it’s based on a false dichotomy: the idea that if the things we thought we knew are once proved wrong, then we can’t trust any knowledge at all. In this age of post-truth politics and climate-change denial, that’s an uncomfortable message to go home with. There’s a subtler reality about the advance of science, that established orthodoxies crumble away when new discoveries challenge them, which Bad Chemist circles around but doesn’t quite land on.

Overall though, this is a beautifully-constructed play, with visual themes and throwaway comments - even some of those awful jokes - proving to have deep significance later on. If you’ve ever worn a lab-coat, rejoice: at last there is a play which understands speaks to you. And if you haven’t, see it anyway. Dr Rook is perfectly drawn, and I defy you not to love him.