The Speed of Light is Not Constant
The speed of light in a vacuum is a fundamental constant of the universe, approximately 299,792,458 meters per second. However, when light passes through different materials, such as water or glass, it slows down. This phenomenon is due to the interaction of photons with the atoms and molecules in the substance, causing them to be absorbed and re-emitted. The speed of light in a medium is described by the refractive index of that material. This is the basis for the bending or refraction of light as it enters a different medium, like water or a glass lens. It’s a fascinating demonstration of how the behavior of light can change in different environments.