We experimented with time travel this week and it raised bigger questions than I expected.
As part of a Victorians project, we took the children to a classroom recreated to look as it might have done 120 years ago.
You know the kind of thing. Big map on the wall, most of it coloured Empire pink, strict lines of wooden desks with fold-up seats, and a hyper-assertive Victorian teacher, played by an actress trying to convince herself that theatre in education is a gateway to Hollywood.
But what really impressed the children was the blackboard. You could scribble stuff on it with chalks, you could write or draw and when you were finished you used a scrubber and it disappeared. How cool is that.
You have to remember that these seven and eight-year-olds have grown up with interactive whiteboards. When their generation gets nostalgic, they'll be talking about broadband wireless iMacs the way that we talk about the Magic Roundabout.
So the blackboard, operated with hand and chalk, was an unknown quantity, exciting and surprising - and what they liked about it most was the idea you could just write something and then rub it away if you didn't like it.
I can remember having similar feelings the first time I used a word processor.
And the actress-teacher seemed to be enjoying the tough-girl act, flexing an impressive looking stick and getting the children to copy the copperplate handwriting on the blackboard.
When a couple of our children, well-versed in the feelgood DIY psychology of children's television, asked why we couldn't debate more about what we were going to do in the afternoon, the Victorian teacher couldn't wait to let rip.
"You'll do what I say and there's no debating it. If I ask you to jump, the only question is 'How high, miss?' This is for your good, it's your moral duty, it's what your parents expect, it's what Queen Victoria herself would expect."
On the coach back, listening to the occasional sound of children threatening to vomit, I began to think about that Victorian classroom.
I envied the sense of purpose. Not necessarily what we would agree with now - but there were no blurred edges. Education was good for you. Learning to read and write was a moral good, it was making a better world, it was building a civilisation.
Now I know that didn't match up to the reality - children were put up chimneys, empire builders were ripping the wealth out of other countries at gunpoint.
But for the teacher in the class, there was a clear sense of direction. It was about self-improvement, building a better life. For many teachers, education had been their own escape from tough industrial jobs.
How about us, when we have to threaten parents with imprisonment to get them to send their children to school? Why are we teaching? What are we doing with our interactive screens? No one believes in education for its own sake any more, so does that mean we're just improving speeds in the rat race?
At a training day at the start of term, all the local ICT co-ordinators were asked to contribute to a blog, to share the problems facing colleagues. I can write the who, what, where - but it's never going to tackle the trickier question of "why?"
We might have technology that makes learning more efficient, but to what end? We might talk about helping children fulfil their potential, but what does that really mean? Turning them into model workers for the online employer? Giving them the ICT skills to work long hours in front of a screen?
Thirty years ago, we could believe that technology was going to improve our lives, that it was going to create a leisure age. Instead, it meant one person doing three people's jobs. Even 20 years ago, we thought that improving technology was inherently good. The faster the modem, the better the world.
But what about now, when we're post-modern, post-belief, post-political? We've got technology in the classroom that would have seemed remarkable a decade ago. But what do we want to achieve with it? Answers on the blackboard.