Characteristics properties of materials

Question 1

Density

Answer 1

The mass of a material (its weight) divided by its volume (size)

Question 2

Strength

Answer 2

The strength of a material is its ability to withstand forces that try to bend or break it
- some materials might be strong against one type of force but weak against another

Question 3

Tenacity

Answer 3

The strength of textiles and fabrics

Question 4

Compressive strength

Answer 4

Withstanding compressive/ squashing forces

Question 5

Yield strength

Answer 5

Withstanding forces before being permanently deformed

Question 6

Impact strength

Answer 6

Withstanding sudden force

Question 7

Tensile strength

Answer 7

Withstanding tension/ stretching force

Question 8

What materials have a high tensile strength but low compressive strength?

Answer 8

Composite materials, timber and some polymers

Question 9

What has tensile and compressive strength?

Answer 9

Metals usually have tensile and compressive strength

Question 10

Hardness

Answer 10

The hardness of a material is how resistant it is to pressure from cutting, scratching or wear (metals are harder than polymers and textiles

Question 11

Brittle

Answer 11

A material that will shatter or break rather than bend and deform when a force is applied

Question 12

Durability

Answer 12

The ability of a material to withstand wear, pressure or damage

Question 13

Strength to weight ratio

Answer 13

A measure of a material’s strength compared to its weight

Question 14

What materials have a high strength to weight ratio

Answer 14

Most polymers
Carbon fibres
Glass fibre
Alloys (e.g. titanium)

Question 15

Stiffness

Answer 15

The ability of a material to resist being deformed when a force is applied to it (its rigidity)

Question 16

Examples of rigid materials and examples of materials with poor stiffness…

Answer 16

RM
Ceramics
Glass 
Steel
PS
Polymers like foam and rubber

Question 17

Elasticity

Answer 17

The ability of a material to return to original shape when forces are applied that will make it bend or flex out of shape

Question 18

What will materials with low elasticity do?

Answer 18

Deform very little before breaking

Question 19

Impact resistance

Answer 19

The ability of a material to withstand a force or shock applied to it

Question 20

What materials have good impact resistance?

Answer 20

Soft metals such as mild steel

Polymers such as rubber and nylon

Question 21

Plasticity

Answer 21

The ability of a material to permanently change in shape when a force is applied to it

Question 22

Corrosive resistance

Answer 22

How susceptible a material is to degradation from oxygen, moisture and other chemicals

Question 23

What is rust?

Answer 23

A form of corrosion that affects ferrous metals when they are exposed to oxygen and moisture

Question 24

What materials are resistant to corrosion?

Answer 24

Oak and dense hardwoods

Question 25

What materials will rot when exposed to elements and left untreated?

Answer 25

Softwood

Question 26

What can be affected by the weather?

Answer 26

Car and bicycle tyres will crack and split if left in the sun

Question 27

Flammability

Answer 27

The ability of a substance to burn or ignite

Question 28

What types of materials are flammable?

Answer 28

Most timbers Polymers Fabrics Papers and boards

Question 29

What is not flammable?

Answer 29

Metals

Question 30

Absorbency

Answer 30

The ability of a material to absorb / take in moisture

Question 31

What materials have good absorbency?

Answer 31

Natural fibres (e.g. cotton, linen, wool) Cardboard Foam

Question 32

Thermal conductivity

Answer 32

Materials with good thermal conductivity allow heat to be transferred through then easily

Question 33

What are good conductors of heat/electricity ?

Answer 33

Metals

Question 34

Thermal resistance

Answer 34

Materials with good thermal resistance will not let heat be transferred through the easily - good insulators

Question 35

Porous

Answer 35

``` A material that has tiny holes that allow moisture to seep through Porous materials (Styrofoam and softwoods) are good insulators ```

Question 36

Thermal fabrics

Answer 36

E.g. acrylic, wool and viscose Have good insulation (material that prevents heat, electricity or sound from escaping) properties. Used to keep clothing warm, keep things cool in cool bags

Question 37

Electrical conductivity

Answer 37

Refers to how easy it is for electricity to flow through a material

Question 38

Good electrical conductor

Answer 38

Metals

Question 39

Bad electrical conductor

Answer 39

Wood and rubber

Question 40

Magnetic properties

Answer 40

A material with magnetic properties will emit forces that attract or repulse other materials