As any teacher will tell you, there is nothing that enthuses, excites, enthrals and focuses pupils more than this.
No, I'm not talking about that superb lesson, it's much more important than that - it's white, looks like cotton wool and is icy cold. Yes, I'm talking about snow.
Can you see that single flake dropping from the sky? It is that, more than anything, causing great excitement among pupils. The only thing on their minds now is whether the school is going to shut and consequently how long will they be off.
No teacher has a chance of inculcating more knowledge, and the more the snow is falling the less chance they have. A maths teacher might see this as an example of inverse proportionality, but that is all that will be taken in during the lesson.
Mobile phones don't help teaching either. "My mam has just rung to say the buses are going to stop."
"My mam says there's four inches where I live."
"My friend has just rung to say her school is going to shut."
Of course the calls may be false but any chance of teaching is fast disappearing.
The day wears on. More and more panic is apparent as less and less is learned. Snow vies with a buzzing wasp as the greatest disturber of the equilibrium of the classroom. Teachers, too, start to panic. The further away a teacher lives from the school the less likely they are to have an interest in teaching.
Break-time arrives. The pupils pelt one another with snowballs. After break very wet, very cold pupils troop back into class. There appears to be fewer of them. Some brave souls have walked home to the consternation of the others, who feel cheated that they may have to work.
However, they make frequent looks out of the windows, and their cold fingers and water on books soon puts an end to all attempts to teach. The teacher repeats that the decision to close the school is not theirs.
It is lunchtime and the snow inexorably falls, many more snowballs are pelted and girls have wet necks from boys putting snow down their backs.
Now everyone is exasperated that the school is not shut. The headteacher ponders how long he can control the erupting masses. He phones the local authority to ask if he ought to shut the school. They prevaricate and say it's his decision.
Form teachers dejectedly call registers to fewer pupils. Lessons begin but, by now, nobody is interested in learning.
All the school is concentrating on snow, snow, snow. At last great joy as the bell rings early and all go home relieved.
Nothing has been learned. The snow has won. From that first flake education was doomed. Next year will be the same, too.