PHYSICAL PROPERTIES

Question 1

what is a physical property

Answer 1

a characteristic of a material that can be measured or observed without changing its chemical structure

Question 2

what is a working property

Answer 2

how a material responds when it is manipulated or worked

Question 3

examples of physical properties

Answer 3

absorbency
density
electrical conductivity
thermal conductivity
fusibility

Question 4

what is density

Answer 4

the mass per unit volume of any material. how solid a material is

Question 5

what is fusibility

Answer 5

the ability of a material to be converted from a solid to a fluid state by heat and combined with another material

Question 6

ductility definition

Answer 6

the ability of a material to be stretched or drawn or pulled without breaking
-> ability to be drawn into a wire

Question 7

elasticity definition

Answer 7

the ability of a material to return to its original shape after stretching or compressions

Question 8

hardness definition

Answer 8

ability to withstand impact, wear, abrasion and indentation

Question 9

malleability definition

Answer 9

ability to be bend and shaped without cracking or splitting

Question 10

strength definition

Answer 10

ability to withstand a force such as pressure, compression, tension or shear

Question 11

toughness definition

Answer 11

ability to absorb shock or impact force without fracturing

Question 12

go over properties and uses of paper, card and board

Answer 12

slay

Question 13

what are hard woods and give examples

Answer 13

• woods that come from deciduous trees (trees that loses its leaves in a particular season)
  examples:
  ash, mahogany, oak, beech, balsa

Question 14

two differences between hardwood and softwood

Answer 14

• hardwood comes from deciduous trees, softwood comes from coniferous trees
• deciduous trees are slower growing, which makes wood denser

Question 15

what are softwoods and give examples

Answer 15

wood that comes from a coniferous tree (doesn’t lose it’s leaves and usually bears needles and cones)
examples:
pine, spruce, larch

Question 16

Examples of manufactured timbers

Answer 16

Plywood
Chipboard
Medium density fibreboard (MDF)

Question 17

advantages of using natural timber

Answer 17

• aesthetic appeal : attractive grain and texture patterns
• non toxic: can be used in furniture and children’s toys

Question 18

disadvantages of using natural timber

Answer 18

• expensive, especially hardwoods
• requires regular maintenance such as sealing, oiling etc to protect it from external factors such as sunlight and water
• stock size is limited, they come in planks

Question 19

advantages of manufactured timber

Answer 19

• available in multiple large board sizes, reducing the number of joins
• cheaper than natural timber
• easily cut
• can be easily laminated to apply a wide range of finishes

Question 20

disadvantages of manufactured board

Answer 20

• dense, making them very heavy n sheets
• edges are difficult to finish because they don’t have a natural end grain
• not as attractive/appealing as natural timbers

Question 21

what is a ferrous metal

Answer 21

a metal which contains iron and have high tensile strength and durability

Question 22

examples of ferrous metals and their uses

Answer 22

• cast iron metal: manhole covers: hard but brittle and resists deformation and rust
• low carbon/mild steel: steel building frames: tough and ductile. rusts easily if not protected
• high carbon steel: hard but brittle, resists abrasion and retains its shape. used in tools, blades and scissors

Question 23

explain two factors that make a metal an expensive material to obtain

Answer 23

• mining is very dangerous and often very remote
• mining machinery is expensive to buy and operate
• techniques often use dynamite, destroying the earth’s surface

Question 24

what are non ferrous metals

Answer 24

metals that are a group of pure metals and do not contain iron

Question 25

properties of non ferrous metals

Answer 25

• non magnetic so it’s used for wiring and electronics
• higher resistance to rust but can corrode or oxidise
• commonly used externally for guttering , pipes and road signs

Question 26

what is an alloy

Answer 26

alloys are mixtures of at least one pure metal and another element to improve working properties or aesthetics

Question 27

examples of alloys

Answer 27

high speed steel
stainless steel
brass
bronze

Question 28

advantages of alloys over pure metals

Answer 28

alloys are generally harder and denser thana most pure metals
alloys often have better corrosion resistance than a pure metal
- easier to manipulate it into different forms

Question 29

what is a thermoforming polymer

Answer 29

a polymer when heated, can change it’s shape again

Question 30

what is a thermosetting polymer

Answer 30

a polymer which when is heated, CANNOT be reshaped again

Question 31

comparison of thermoforming and thermosetting

Answer 31

thermoforming: more flexible
thermosetting: resistant to higher temperatures, burn when heated, harder, more brittle, good insulators and have a higher chemical resistance

Question 32

examples of thermoforming plastics

Answer 32

• HDPE
• poly propylene
• HIPS
• Acrylic
• PVC: poly vinyl chloride

Question 33

examples of thermosetting plastics

Answer 33

-polyester resin
- urea formaldehyde
- melamine formaldehyde
- epoxy resin