Theory - Materials Flashcards
………..are those that describe how a material behaves under a specific condition.
Physical properties
What is Fusibility and when is it needed
How easily a material’s state can be altered to become a liquid.
An important property in soldering, where the low melting point allows it to melt with the heat of the soldering iron.
What is Electrical Conductivity
Give an example of a good electrical conductor
How easily electrical energy can pass through a material
Gold is excellent at this, but is an expensive material. Used in small quantities in high-end electrical components.
What is thermal conductivity and give an example of a good thermal conductor
Can be described as how easily heat energy can pass through a material.
Aluminium is a excellent conductor of heat, which makes it a popular choice when manufacturing pots and pans
What is resistance to moisture, give an example material
A material’s ability to prevent liquid and moisture from permitting its surface.
PVC has excellent moisture-resistant properties and can be added to coating fabrics that can be sed in waterproof clothing.
Other hydrophobic coating can be applied to fabrics to achieve a water-resisitant coating.
What is absorbency and what is it used for
Defined as a material’s ability to soak up and retrain liquid, heat or light.
Is an important property when related to fabrics
Give some examples of high absorbency and low absorbency materials
Natural fibres such as cotton and wool have high absorbency, making them comfortable to wear as they absorb perspiration.
Synthetic fibres are virtually non-absorbent so can be very uncomfortable to wear. (Like wearing a plastic bag).
…………………..describes how it behaves when being worked or shaped
Mechanical or working properties
What is strength
The ability of materials to withstand a constant force WITHOUT BREAKING.
What are the 5 forces that can act upon a material
Compression Tension Bending Torsion Shear
What is hardness
The ability of a material to withstand cutting, scratching and abrasion.
What is a material which is very hard
Melemine formaldehyde is regularly used in kitchen work surfaces as it maintains a smooth polished finished due to it’s hardness.
It’s also a thermosetting plastic.
What is density
And what is used because of it
A materials mass per unit volume
Polystyrene is used in packaging for protecting expensive or fragile objects.
What is toughness
A materials ability to withstand impact from a dynamic force.
What product needs to be tough and what is it made of
Children toys are subjected to huge amounts of wear.
Often left outside so need to be durable.
HDPE is used for the children car due to it’s excellent toughness and wide range of colours.
