Lesson 21: Categories of Materials
Everyday objects are made from materials chosen for particular jobs. Wood, metals, plastics, glass, and other examples introduce material groups, natural origins, processing, and synthetic materials.
Key Ideas
- We can group materials by what they are, such as metal, wood, plastic, glass, rubber, leather, or fibers.
- Some materials come from nature. Others are made through chemical processes. Shaping a natural material does not automatically make it synthetic.
- An object can contain several materials. Each part may need a different material for its job.
- A material’s properties help us decide how to use it. A raincoat needs to keep water out, while a window needs to let light through.
- Different materials suit different jobs. No single material is best for every use.
Vocabulary
- Material: Any substance that objects are made from.
- Natural: Originates in nature, such as wood, cotton, or stone; people may still process it.
- Synthetic: Made through chemical processes, such as polyester fabric.
- Fiber: A long, thin strand that can be twisted or woven into things like thread or fabric.
- Composite: A material made by combining different materials so they work together.
Discussion Questions
- Why do you think different parts of the same object are made from different materials? Can you think of an example?
- What properties make a material useful for a particular job? For example, why might a cooking pan need a different material than a towel?
- Can you think of something made from several different materials? What job does each material do?
- What is the difference between a natural material and a synthetic material? Can you name an example of each?
- Pick an object near you. What materials is it made from, and why do you think the designer chose those materials?