Huygens-Fresnel principle

Okay kiddo, so imagine you have a ball and you throw it across a room. When you throw the ball, it moves in a straight line until it hits something and then bounces off.

Now, let's think about waves. Waves can be things like sound waves or light waves. They travel through a medium, like air or water, and they can also bounce off things like the ball.

But waves are different than the ball, because they don't just move in a straight line. They can bend and change direction as they travel.

So scientists wanted to figure out how waves, like light waves, move and bend. They came up with something called the Huygens-Fresnel Principle.

Basically, the principle says that each point on a wave acts like it's own little wave, and sends out new waves in all directions. These new waves interact with each other and change the overall shape of the wave.

Think of it like throwing a bunch of pebbles into a pond. Each pebble makes its own ripples, but the ripples from all the pebbles combine and make bigger ripples. The same kind of thing happens with waves.

So the Huygens-Fresnel Principle helps us understand how light waves can bend around corners, and how different waves can interfere with each other to create patterns of light and dark. It's pretty cool stuff!