Well, kiddo, characterization in materials science is like playing pretend detective with really tiny things that can't be seen with our eyes. You know how you use clues to figure out who the mystery person is in a game? Scientists use different tools to figure out what materials are made of and how they behave. They do this by studying the physical and chemical properties of materials at a very small scale.
For example, they might use a microscope to look at a material up close and see what it looks like. Or they might use something called X-rays to see how atoms are arranged inside the material. They might even use a machine that can pull on a material to see how strong or flexible it is.
All of these different methods help scientists understand what a material is made of, how it will behave in different situations, and how it can be used in different applications. So just like how a detective can solve a mystery by looking at clues, scientists can understand materials by studying their properties and characteristics.