When it is summer (like now) and the sun sets here around 10 pm, my son can put his head on the pillow for 5 mins, get up, see there is light outside (by leaving his room, as his rooms is dark) and exclaim: "It is now morning!". He is not always convinced that we are not lying to him when saying that is still evening / night.

Maybe it gets easier to explain when they have a better understanding of time? Understanding time has past and how much of it seems to be difficult for kids to grasp / understand ? (I have no clue, just observing my own small world).

I guess the same could be said for adults though, our concept of time often depends on whether or not we want to do what we are doing - time flies and so on. Sorry for the tangent!