Imagine you're playing with tiny building blocks called atoms. One of the building blocks is called silver and another one is called halide. When these two building blocks come together, they form a new block called silver halide.
Now, let's imagine we have a camera film that works like a window. When you take a photo, the light shines through the window and lands on the silver halide blocks. This light energy is like a hug that makes the silver halide blocks change in a special way.
Once the photo has been taken, the film is bathed in chemicals that help to develop the image. These chemicals make the silver halide blocks change into silver, which is darker and can be seen better.
So, silver halide is a special building block that helps to create images on camera film. When light shines on it, it changes and creates a photo that we can see.