Sources and Origins of Materials

• Materials come from a variety of sources, each with its own properties, benefits, and drawbacks.
• Natural materials, like wood and wool, are derived directly from plants and animals.
• Synthetic materials, such as plastics and artificial fibres, are human-made, often created by modifying natural substances.
• Metals are typically extracted from ore, a naturally occurring solid material. The ore is heated in a furnace to obtain the metal.
• Often materials can be recycled to reduce wastage and environmental impact. Metals, glass, and many types of plastic can be reheated and reshaped.
• The process of obtaining materials can be energy-intensive and can often have a substantial impact on the environment, making sustainable sourcing a pivotal consideration in design.

Physical Properties of Materials

• Physical properties describe how a material reacts to forces, light, heat, and other physical phenomena.
• Density is a measure of the mass of a material per unit volume. It can inform selection for applications where weight is a factor.
• Boiling and melting points determine how a material will respond to heat. For instance, metals generally have high melting points, making them suitable for settings with significant heat exposure.
• The colour, texture, and aesthetic qualities of materials must also be considered in design, particularly in product or housing design where visual appeal is significant.
• Some materials can withstand many stress cycles or large deformations without breaking, a property known as ductility. Materials high in ductility, like some metals, can be used in applications requiring plastic deformation.

Working Properties of Materials

• Working properties refer to how a material responds to the process of being worked or manipulated.
• Workability determines how easily a material can be modified into a different shape. For example, many metals can be hammered or rolled into thin sheets.
• Machinability describes how a material reacts to being cut or shaped by a machine. Good machinability means the material can be cut easily and cleanly.
• Materials must also be able to withstand the forces that will be applied to them in their final form. This is called strength.
• Some materials may change properties when subjected to different conditions, like extremes of temperature or pressure. Understanding how these changes affect the material is essential in engineering design.

Components and Systems

• A component is a single item that is part of a product, like a screw or a wheel.
• A system is a group of components that work together to perform a specific function in the product, like a bike's braking system.
• Components can also be classified as standard or specialised. Standard components are widely available and can fit into multiple products or systems, whereas specialised components are designed for one specific product or system.
• Complex systems can be subdivided into subsystems to simplify analysis and design processes.
• All components and systems will have limits of operation, which must be strictly adhered to in order to avoid system failure.