Fresnel reflection

Imagine you are in a swimming pool and you have a ball. When you throw the ball into the water, you can see that the ball seems to disappear as it hits the surface. This is because the water reflects some of the light, making the ball appear to be less bright.

Now, imagine that instead of a ball, you have a beam of light hitting a surface, like a piece of glass. Some of the light is reflected off the surface, like the ball bouncing off the water, and some of the light passes through the glass.

But here's the thing: the angle at which the light hits the glass affects how much light is reflected and how much passes through. This is called the Fresnel effect, named after the guy who came up with the idea.

When the angle of the incoming light is shallow, more of it is reflected off the surface, making the glass look shiny. When the angle is perpendicular, almost all of the light passes through the glass, making it transparent.

So, in summary, the Fresnel effect is how light behaves when it hits a surface, and how the angle of the incoming light affects how much is reflected and how much passes through.