Pre-school physics

My daughter asked me if I could think of some physics experiments for pre-school children in other words her son, my grandson (obviously), Hugo. Physics is all about the relationship between measured quantities and its a bit difficult to measure something if you can't count. Actually Hugo can count, he understands that numbers represent things but I am not sure that he understands that numbers also represent measurement, maybe he does but for the sake of argument let's say he doesn't. We use graphs to show linear relationships but I think graph plotting may be beyond the scope of a pre-schooler. However if the length of an object is proportional to some quantity then we can use the object to plot a graph rather than taking measurement.

The idea I came up with is to use springs and a set of different length masses to demonstrate Hooke's law. You need 5 identical springs and 5 masses of different length but same cross sectional area, the length of the mass is therefore proportional to the mass. Start by hanging a series of springs next to a board. Attach the masses randomly to the springs and mark the board at the extended length. The challenge for the child is to put the correct mass on the spring so that it extends by the correct amount. The next challenge is to arrange them in order to get a sort of mass vs extension graph. The aim being to understand that extension is related to mass.

I think that this could be a great activity for students. Not the experiment itself but the challenge of creating activities to teach basic concepts to pre-school children.