Warm Up # What are some physical properties that are used to evaluate materials?

Technology and the Design Process Lesson 2: Materials and Their properties

Essential Questions How are materials selected for a designed product? Why are materials modified to change their properties? How are materials classified?

Properties of Materials Physical property – a characteristic that can be observed or measured without changing the identity of the material Include magnetism, conductivity, density, solubility, melting point, and boiling point

Physical Properties Activity Identify the physical properties of the following objects:

Properties of Materials Chemical property – the ability or inability of a substance to combine with or change into one or more new substances Ex: rust, flammability, burning, corrosive, pH level Why is the ability to rust a chemical property?

Properties of Materials Mechanical properties – characterizes that determine how a material reacts to forces

Types of Materials Wood – most common material used to build houses, make toys and furniture, provide fuel, etc. Polymers – natural or manufactured materials composed of long chains of small, repeating molecules Ex: plastics is an example of this Plastics – usually lightweight, strong, waterproof, and inexpensive

Types of Materials Composite material – a mixture of 2 or more materials, 1 layered in the other Used to make automobile bodies strong, lightweight, and rust resistant Alloy – a mixture of 2 or more materials Used when the properties need to be improved for an application, like hardness, strength, density, or durability Ceramics – mixtures that are produces to achieve desired properties