When you're five, time has no fixed meaning. The stretch from Scooby-Doo to bathtime flashes past in an instant. The year between birthdays is roughly equivalent to the era from the Big Bang to now. Eating your broccoli can last longer than the summer holidays.
But is this phenomenon innate or environmental? Because, in the infants, time runs strangely for everyone.
For instance, there is laminator time. This is the period it takes the school laminator to reach a temperature sufficient to plasti-mount the alphabet (lower and upper case), or a selection of farm animals. That's slightly hotter than the centre of a hot apple pie from the Earth's core branch of McDonald's. Even so, waiting for the "ready" beep takes forever.
Pages fall from the calendar. I watch my fingernails grow. New-born babies enrol, and are halfway through reception in the time it takes to feed a plastic sheet through the rollers. And yet laminator time is like Narnia time. Back in the classroom, it's like I've never been away.
Then there's playtime. Watch the children from the window, and reality obeys Einsteinian principles. No one approaches the speed of light, or comes back in before they've gone out (except a couple of Year 2 girls who need the toilet). But hear the children speak, and playtime lasts an eternity. Wars are fought. Cup finals are won. Friendships are forged and broken. So how come, in the staffroom, there is only enough time to drink half an inch of a cup of tea?
Thirdly, we have work time. This is where Teacher produces any number of complex activities for the morning session, and brings them all to a close precisely as the dinner ladies serve lunch. Or, for the parent-helper, the phenomenon by which, however much time I am given to complete an activity, it's never enough. So at 11.50am, as I frantically urge two boys to stick arms, legs and hair on their African peg dolls, I realise I must be the unwieldy variable in Teacher's precise-time equation: the intricacy of the task (high) x the attention span of the child (low)the attention span of the supervising adult (sorry, what was the question?).
I try my best. Today, I keep a regular eye on our progress via the clock on the wall in the play corner. It's only later I realise the clock in the play corner is cardboard.
Michael Cook is a freelance copywriter and a parent helper at Ernehale infants school, Arnold, Nottingham, which his children, Alfie and Poppy, attend