I have started a lesson on the sun and shadows before with a video on shadow puppets and letting the children explore and discuss how to create the best shadow. I have then taken the lesson outside to play a game of shadow tag. Usually, some children will figure out how a shorter shadow makes it more difficult to catch them. You can pause the game to explore and discuss this drawing the children’s attention to the position of the sun before letting them continue the game and see if they can apply this knowledge to shorten their shadow to make it more difficult to catch them.
I liked the idea of getting the children to bring in a teddy as a scientific buddy to trace it’s shadow and check through the day how the shadow has moved.
Older classes I have had have really engaged with the story of Aristotle noticing how something round cast a shadow on the moon and deduced from that that the earth is a sphere and not flat.
I have made sundials before with paper plates stapled together weighted down with sand or pebbles and using a shortened barbecue skewer. They worked ok but blew away easily even when weighted down. The kids really enjoyed designing their own sundials though and looking at past designs.