I don't expect to show how electrons move :) I mean, some model, a toy or so, that shows how these things work. I remember it only from books/specs, but even there, at a certain point there are "limits" :)
When my kids were less than 10 I took them to the Computer History Museum in Mountain View CA and showed them how all the mechanical computers work. They have some exploded and simplified exhibits that are very visual so kids can get it pretty easy. Especially if they’re the kind of kid that builds with blocks. Games like Turing Tumble are good too. Then you just wave your hands and say chips work like this on the inside, but with electricity instead of gears because it’s faster, smaller, cheaper and uses less energy. But at the end of the day, it’s basically all clockwork. Then they smile and say, “makes sense”. And I leave it at that.
When the kids were teenagers I gave them a more thorough explanation.
If you’re not in the Bay Area then the Computer Museum does have YouTube videos. There are many others as well.
https://m.youtube.com/watch?v=XSkGY6LchJs&pp=ygUbbWVjaGFuaWN...