How do the shadows change during the day?

Shadows are everywhere. It is not always easy to understand this phenomenon. What makes the shadow of an object? How do we explain its shape? Why does this dark zone attached to an object evolve throughout the day?

The objective of this animation is to respond to these questions. The setting is simple to be able to isolate the effects of the light source (here it is the sun) on the objects (here it is the tree with or without the house). While displacing the sun the shadow ellongates, retracts or disappears. The light disseminates in a straight line. It is therefore easy to understand that the shadow reproduces the silhouette of a more or less deformed object according to the position of the sun.

Click to slide the sun in the sky.