This could be a fun way to create Calder acrobats! Swing From An Empty Shoe Box Project For Kids - by Krokotak - == - By Russian educative website Krokotak, here is a cool project for kids, with a tutorial full of photos that dispenses words.
Trace the shadow of your sculpture - foil figure or another object with a clearly identifiable shape. Ask, "If I hold the light here, will the shadow move?" Explore how the shadow elongates and shortens as the light is moved.