Son1 peered at a picture of a typewriter the other day. “What’s that?” he asked, tilting his head to see it from a different angle, screwing his eyes up a bit … “it doesn’t look like a MacBook.”

In fact, barely a day goes past when my children don’t remind me that lots of the things I grew up with amount to ancient history in their eyes. This weekend was a prime example – another reminder that time is like a rubber band, shooting us out into the unknown.

A leap of the imagination: ‘Yes, you had to plod over there and turn a dial!”

Saturday morning is homework morning in our household and definitely not a highlight of the week. If there’s one time I’d love to go running off into the desert, far, far away from the sounds of my son protesting loudly and scraping his chair back as he disappears on yet another unexplained errand, it’s Saturday morning.

This weekend, Son1 had to research three inventions. I was thinking toasters, lightbulbs, the telephone. I started telling him about Alexander Bell. Turned out he was thinking TVs, iPads and the X-Box.

We settled on TVs, helicopters and cars, and he set about finding out three facts for each.

For TVs, he learnt that images used to be broadcast in black and white (quick aside: remember how the picture on old TV sets used to shrink to a dot before turning off?). Warming to the theme, I told him that, when I was a baby, my own mother watched the moon landings on a small monochrome screen.

“Wow!” he exclaimed, rabbit-eyed in wonder. “Black and white!” (Never mind that they got to the moon and back with as much computing power as you’d find in a mobile phone.)

The next fact he found out was that remote controls became available in the 1980s, heralding a whole new lifestyle of motionless.

He hesitated, collecting his thoughts in the sponge-like part of the brain with which children soak up information. “But how, mummy,” he said, scratching his head, “did you change channels before remote controls?”

“Well,” I replied, my facial muscles twitching, “how do you think we did it?”

“Did you have …” There’s a pause … “buttons on the TV?”

“Yes! We had to get up … imagine THAT!”