Understanding Raw Materials, Properties, and Technological Products

Raw Materials and Their Properties

Raw materials are substances extracted directly from nature. They can be classified as:

• Animal: Leather, wool, silk
• Vegetable: Flax, esparto, wood
• Mineral: Iron ore (hematite), clay

A material ready for processing is called a field-ready material. These materials undergo physical and chemical transformations to create products like paper, board, and wood.

Technological Products

A technological product is any object created by humans to meet their needs and improve their quality of life. These objects are made from various materials (e.g., books, tables). The process of creating technological products involves transforming raw materials into usable materials and then into the final product.

Common Technological Materials

The materials most used to develop technological products are:

• Wood: Comes from the woody part of trees (e.g., spruce, pine). Used for fuel and in the paper industry.
• Plastic Materials: Artificially obtained from oil, coal, natural gas, plant materials (cellulose), and animal proteins (e.g., cellophane, rubber). Used for Tupperware and packaging.
• Metal Materials: Extracted from minerals found in rocks (e.g., iron, steel). Used in structures and machinery.
• Stone Materials: Extracted from rocks in various forms, from large blocks to sand (e.g., marble, slate). Used in construction and decoration.
• Ceramics: Obtained by molding clay and then firing it at high temperatures in an oven (e.g., porcelain, earthenware). Used for dishes and bricks.

Mechanical Properties of Materials

• Mechanical Strength: Indicates a material's ability to withstand stress without breaking.
• Toughness and Fragility: Describes a material's resistance to breaking when impacted (toughness) or its tendency to break easily (fragility).
• Magnetism: Indicates whether a material attracts other metal materials (e.g., iron can become a magnet).
• Electrical Conductivity: Indicates whether a material transmits electricity. Conductive materials allow the passage of current (metals), while insulators do not (wood and plastic).
• Acoustic Conductivity: Indicates whether a material transmits sound. Conductors allow the passage of sound (metal), while insulators do not (plastic and cork).
• Thermal Conductivity: Indicates whether a material transmits heat. Conductors allow the passage of heat.
• Expansion and Contraction: Indicates whether a material increases in size with increasing temperature (dilation) and decreases in size with decreasing temperature (contraction). Metals are particularly sensitive to these changes.
• Fusibility: Indicates whether a material transitions from solid to liquid with increasing temperature (metals, glass).
• Solderability: Indicates whether a material can bond with another material or itself after melting (metals, glass, and plastic).

Textile materials are obtained directly from raw materials or synthetically (e.g., natural yarn). Used in shirt manufacturing.

Physical Properties of Materials

All materials possess a number of properties that distinguish them from each other and determine their usefulness. These properties include:

• Physical Properties: Determined by subjecting a material to stimuli such as electricity (electrical properties), light (optical properties), heat (thermal properties), forces (mechanical properties), and sound (acoustic properties).
• Chemical Properties: Determined by reacting the material with other substances.
• Ecological Properties: Determined by observing the impact of a material on the environment.

Other Physical Properties

• Elasticity and Plasticity: Indicates whether a material returns to its original shape after a force is removed (elasticity) or remains deformed (plasticity).
• Malleability: Indicates whether a material can be spread into plates or sheets (metals, glass, plastic).
• Hardness: Indicates whether a material resists scratching. Diamond is the hardest mineral, and talc is the softest.
• Transparency: Indicates whether a material lets light pass through it. Opaque materials do not allow light to pass through (wood), transparent materials allow light to pass through clearly (glass), and translucent materials allow light to pass through but not clearly (fine cloth).