Have you ever heard the saying "what you see is what you get"? Well, this is basically what truth to materials means. It's when artists and designers use the natural characteristics of materials to enhance their work instead of hiding or disguising them.
Let me give you an example. You know how a tree is made of wood, right? If someone were to make a wooden sculpture, they could use the wood's natural texture, color, and grain to create a beautiful piece of art. They wouldn't paint it or cover it up with anything else, because that would hide the unique features of the wood.
Another example is with buildings. Have you ever seen a brick house? The bricks are usually left in their natural color and texture instead of being painted over or disguised. This is because the bricks themselves are what make the house strong and sturdy, and painting them would not add any extra value.
Basically, truth to materials means using the natural beauty of materials to make something even more beautiful, instead of trying to change or hide them. It allows us to appreciate the unique qualities and characteristics of each material, and it is often used in art and design to create works that are both functional and aesthetically pleasing.