My four year old son (four and three quarters if you ask him) asked me a veriosn of this question while I was scrolling images on my phone recently. I tried explaining, then realised how hard it was to explain, and that to explain if fully was a multifaceted project.
Think about it yourself. Straight off you think “well, they don’t go anywhere”, but if you pull them back down they do ‘reappear’ and so to some extent the ‘code’ of the image is still there. It just stops being visible. So you could say that the image stops being visible and is taken apart, but can be reassembled for your eye if you like. Just ‘pull it back down’.
But from a canvas or processing point of view, perhaps it is actually still there. Maybe it’s not taken apart, and is actually ‘off the top’ in some fashion, and still there in the digital window world.
This existential route then reveals the essentially skeuomorphic nature of the interface. It’s a piece of glass, and while the icons and buttons no longer resemble shiny 3D sweets and lozenges, the idea that our phones are little windows that we can drag and scroll things around within is still the basis of the entire desktop / touch screen metaphor. We accept this, but for a cleverly questioning child, it’s revealed as an unnatural and designed interface that has to be learned.
I don’t know, maybe I’m over thinking it, but it felt interesting when it happened, and made me happy that I’m encouraging my kids to question why.