You have probably seen patterns of light like this in a pool of water. What causes it?

1. Absorption

   No. If the light was being absorbed, the pattern would be dark instead of bright.

2. Diffusion

   No. Diffusion is the scattering of light as it is reflected in many different directions. Diffusion would make the entire area brighter, not a specific pattern.

3. Reflection

   No. While the light has to reflect back to your eye for you to see it, reflection does not cause this pattern.

4. Refraction

   Yes! Refraction bends light. Waves and ripples on the surface of the water act just like the curved surface of a lens. This bends the light into patterns that have shapes similar to the ripples on the water's surface.

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