Snell's Law is a really cool idea that helps us understand how light moves through different materials! Here are some important points to know:

• Basic Formula: The main idea is shown by the formula $n_1 \sin(\theta_1) = n_2 \sin(\theta_2)$. In this, $n$ stands for something called the refractive index, and $\theta$ is the angle at which the light hits or bends.

• Refraction: When light travels from one material to another, it bends. How much it bends depends on how different the refractive indices of the two materials are.

• Critical Angle: When light moves from a thicker material to a thinner one, there’s a special angle called the critical angle. At this angle, light bends right along the edge. If it goes beyond this angle, it reflects completely back into the thicker material instead of going through.

In short, Snell's Law helps us understand how light behaves at the edges of different materials!