DP DT Topic 4.1

Transparency

Ability to allow light to be transmitted with minimal scattering allowing a clear view through material.

Chemically inert

Lack of reactivity with other materials.

Non-toxic

Absence of toxic breakdown products/lack of reactivity.

Biocompatibility

The product ensures the continued health of a biological environment.

Brittle

Breaks into numerous sharp shards.

Aesthetic appeal

Favourable in terms of appearance.

Electrical insulator

Reduces transmission of electric charge.

Mass

relates to the amount of matter that is contained with a specific material. It is is often confused with weight understandably as we use Kg to measure it. Mass is a constant whereas weight may vary depending upon where it is being measured.

Weight

relies on mass and gravitational forces to provide measurable value. Weight is technically measure as a force, which is the Newton, ie a mass of 1 Kg is equivalent to 9.8 Newtons [on earth].

Volume

is the quantity of three-dimensional space enclosed by some closed boundary, for example, the space that a substance solid, liquid, gas, or shape occupies or contains

Density

is the mass per unit volume of a material. It's importance is in portability in terms of a product's weight and size. Design contexts include, pre-packaged food (instant noodles) is sold by weight and volume, packaging foams.

Electrical resistivity

This is a measure of a material's ability to conduct electricity. A material with a low resistivity will conduct electricity well.

Thermal conductivity

A measure of how fast heat is conducted through a slab of material with a given temperature difference across the slab.

Thermal expansion

A measure of the degree of increase in dimensions when an object is heated. This can be measured by an increase in length, area or volume.

Hardness

is defined as the resistance a material offers to penetration or scratching.

Aesthetic characteristics

Aspects of a product that relate to taste, texture, smell and appearance.

Ductility

The ability of a material to be drawn or extruded into a wire or other extended shape.

Elasticity

The extent to which a material will return to its original shape after being deformed.

Mechanical properties

Properties of a material that involve the relationship between stress and strain or a reaction to an applied force.

Stiffness

is the resistance of an elastic body to deflection by an applied force. This property is an important consideration for an airplane wing or a downhill skateboard, where maintaining shape is crucial to performance.

Stress

is defined as the force per unit area of a material and is normally determined by applying a tensile force to a sample of material.

Strain

The response of a material due to applied stress, defined as the change in length divided by the original length.

Tensile strength

The ability of a material to withstand pulling forces.

Toughness

The ability of a material to resist the propagation of cracks.

Work hardening

Also known as strain hardening or cold working, is the strengthening of a metal by plastic deformation. This strengthening occurs because of dislocation movements and dislocation generation within the crystal structure of the material.

Young Modulus

also known as the tensile modulus or elastic modulus, is a measure of the stiffness of an elastic material and is a quantity used to characterise materials (stress/strain).

Compressive Strength

The ability of a material to withstand being pushed or squashed.

Plasticity

The ability of a material to be changed in shape permanently