UNIT 1.7 - SMART AND MODERN MATERIALS

Question 1

SMART MATERIALS

Answer 1

• A material whose physical properties change in response to an input or change in the environment, such as electricity, pressure, temperature or light

Question 2

MODERN MATERIALS

Answer 2

• A material developed through the invention of new or improved processes, as a result of man-made materials or human intervention

Question 3

THERMO-CERAMICS

Answer 3

FEATURE: metal powder is placed in a mould or die under high pressure. the high pressure forces the particle particles to bond
PROS: very hard and stable at high temperatures
CONS: brittle material that can break if dropped or hit/imperfections lead to cracks/cost is significantly higher
USES: jet engine turbine blades/car brake disc/space craft heat protection

Question 4

SHAPE MEMORY ALLOYS (SMA)

Answer 4

FEATURE:

Question 5

REACTIVE GLASS

Answer 5

FEATURE: glass reacts to a change in temperature by changing tint. when the glass gets hot, the glass darkens to block the heat from entering through the glass out
PROs: ability to change colour in response to light - offers privacy/replaces the need for separated reading sunglasses
CONS: time delay - may cause difficulty in driving
USES: glasses/apartment windows/roofing

Question 6

LIQUID CRYSTAL DISPLAYS (LCD)

Answer 6

FEATURE: liquid crystals change colour when an electric voltage is applied. the cell turns from the light to dark
PROS: higher resolution - better quality than cathode ray tube/less energy/thinner technology - less materials used/weighs less
CONS: cost/disposal
USES: digital clocks/watches/computer screens/calculator displays

Question 7

PHOTOCHROMIC MATERIAL

Answer 7

FEATURE: changes colour with light intensity
PROS: ability to change colour in response to an applied voltage/reduces the needs for binds/retains heat
CONS: expensive to manufacture/expensive to install
USES: welding goggles/reactive spectacle lenses/security markers/car rear view mirror

Question 8

THERMO-CHROMIC MATERIAL

Answer 8

FEATURE: changes colour in response to temperature change
PROS: dynamically variable/improve safety
CONS: high cost/low colour density
USES: room thermometers/colour change mug or kettles/food packaging for a baby to indicate its temperature

Question 9

QUANTUM TUNNELLING COMPOSITES

Answer 9

FEATURE: insulating rubber containing tiny metal particles. the material is pressure or force sensing, when there is a change in the applied pressure or force, the material changes from electrical insulator to conductor
USES: touch screen technology/smart phone buttons/pressure sensors/speed controllers