An experiment based on an Aesop's fable has shown how differently children and crows learn about the world.
In the story, a thirsty crow drops pebbles into a pitcher of water. Eventually the water level rises high enough for the crow to drink.
Studies have shown that crows really do understand Archimedes's principle. Faced with a food reward floating out of reach in a flask, they will select weighty objects over light ones to displace the water and bring the food within reach.