There is no better way to learn than by making and doing. Our teachers have that concept in mind every time they get ready to teach a lesson.
Recently our third graders made an experiment with a small branch and a bunch of stones, they had to stand the piece of wood using nothing but the rocks; after that, they had to make a mark with chalk on the floor, right where the shadow was.
What a surprise they had when returning after an hour and seeing the shadows had moved.
Now they have a nice story to tell to their grandchildren, from when they learned how to make a clock with nothing but a branch, some rocks, and the shadow.