if you have ever watched a water strider or other insect upon the surface of water, you may have noticed a?

Question

large shadow cast by the contact point where the thin legs touch the water surface. Then around the shadow is a bright ring. what accounts for this?

Answer 1

The insect's feet make dimples in the surface of the water. These dimples act as donut-shaped lenses and focus light into a bright ring.Areas that the light has been refracted away from show up as shadows.