This is an activity that I did with Clara frequently when she was little, but never blogged about and then forgot about for a long time. I finally remembered it because Nancy has been very interested in painting and this is just such a clean way to go about it. I did blog about a giant variation of this in our first summer art series, here.
To do this, you need a box, marbles, some paint, and a spoon. You put your marbles into the paint, stir them around, then drop the marbles into the paint lined box. Then you tip the box around to move the marbles and the paint around. Not only is this an art project, but it is also a physics lesson as you are experimenting with gravity and its effects on the marbles. Or maybe its just fun.
They do come out with some fabulous pictures and it is a good use for the massive amount of black paper that I always seem to end up with. And our painting quota was met for the day.