Why are shadows at noon shorter than in the morning or the evening?

Shadows are shorter at noon because of the position of the sun in the sky. During noon, the sun is at its highest point, directly overhead or near the zenith, depending on the location. This means that the sunlight strikes objects from directly above or at a steep angle, resulting in shorter shadows.

In the morning and evening, the sun is lower in the sky, at an angle closer to the horizon. When the sunlight strikes objects from a shallower angle, the shadows are cast longer. The length of the shadow depends on the angle at which light hits the object, and when the sun is low, the angle of light is more oblique, making the shadows longer.

Thus, shadows are shortest when the sun is highest in the sky, at noon, and they become longer as the sun moves lower in the sky during the morning and evening.