Design Technology - Topic 4.1

Mass

The amount of matter contained in a space

Volume

The amount of 3D space a solid, gas, or liquid occupies

Density

Relationship between mass and unit of volume

Electrical Resistivity

A material’s ability to conduct or resist electricity

Thermal Conductivity

Measures how fast heat moves through a material

Thermal Expansion

The degree to which a material increases its dimensions when its heated

Hardness

The resistance of a material to scratching or penetration

Mechanical Properties

Properties of materials that are usually measured through some form of destructive testing

Physical Properties

Properties of materials that can be measured through non-destructive testing

Tensile Strength

The ability of a material to resist pulling forces

Compressive Strength

The ability of a material to resist pushing forces

Stiffness

The ability to resist bending by a force so that an object maintains its shape when a force is applied to it

Toughness

The ability to deform, but resist cracking/fracturing under impact.

Ductility

The ability to be drawn or extruded into a wire-like form

Elasticity

The ability of a material to bend and then return to its original shape

Plasticity

The ability of a material to be formed into a new shape

Young’s Modulus

Measure of the stiffness of an elastic material using the ratio of stress to strain of a material as force is applied along its length.

Stress

The tensile force applied to a given area

Strain

The percentage of change in length when a force is applied to the initial length

Region of Elasticity

Space on a stress-strain graph where the material would return to its original shape if the material was stretched and then released.

Yield Point

The point on a stress-strain graph where the material will no longer return to its original shape

Ultimate Tensile Strength (UTS)

The point at which the material can maintain a maximum load.

Necking

A mode of tensile deformation where large amounts of strain localize disproportionately in a small region of the material

Failure Point

The point on a stress-strain graph at which the material actually breaks

Aesthetic Properties

Properties that are related to beauty and pleasure derived from a material

Texture

How a material feels or looks

Appearance

The color or pattern of a material

Smart Materials

Reactive materials that change their properties when exposed to stimuli such as electrical charges, moisture, or temperature

Piezoelectricity

The ability to release an electric charge when deformed

Shape Memory Alloys

Materials that allow their bodies to return to their original shape after deforming

Photochromacity

The ability to change color when exposed to light

Magneto-rheostatic fluids

Fluids that undergo a change in their viscosity when a magnetic force is applied

Electro-rheostatic fluids

Fluids that undergo a change in their viscosity when an electrical force is applied

Thermoelectricity

Two different conductors that, when joined together, generate electricity when heat is applied.