Smart materials

Question 1

What is smart material?

Answer 1

A material that changes it properties due to a change in its environment (temperature, sunlight)

Question 2

What material will become translucent when a certain amount of heat is applied?
What is this used for?

Answer 2

Thermochromic liquid crystals

Black when cool, but when heated to a certain temperature, it will become translucent revealing print underneath such as on forehead thermometer.
The bars of colour temperature do not show as the thermochromics crystals do not become translucent as they do not react to that certain temperature.

Can be used to reveal graphics on packaging.

Question 3

What material expands and contracts when electric current is applied causing vibrations?

Answer 3

Piezoelectric crystals

Crystals receive tiny electric charge that cause it to vibrate

Question 4

What is an actuator?

Answer 4

A device for controlling a mechanism
Music card
As a card is opened, the music module is activated as a current is sent to the crystal which acts a tiny speaker driver for the module to create sound

Question 5

What is a transducer?

Answer 5

A device that converts signals from one form to another
Drum kit
When it is struck, voltage is applied to the piezoelectric transducer which turns the signals into digital waveforms which create the desired percussion

Question 6

What ink contains negatively charged black and positively charged white beads in each pixel point?
How does this work?

Answer 6

Smart ink
Altering the charge from negative to positive will cause either the black or white beads to show by leaping to the top of the pit

Question 7

What are the three types of smart ink?

Answer 7

Photochromic- changes in response to light- t shirts change colour in the summer

Thermochromic- changes in response to temperature - drink cups change colour when they cool

Hydrochromic- changes in response to water- umbrellas change colour when it rains

Question 8

What are the advantages of smart ink?

What are the disadvantages of smart ink?

Answer 8

Can be printed on any surface
Used to enhance design and aesthetics
Requires no power

Expensive
Cannot be recycled

Question 9

What material can store details on a product that acts a transponder that can be retrieved by a transmitter?
What are the uses of such a material?

Answer 9

Radio Frequency identification

Keep track on library books

Question 10

Difference between passive and active transponders?

Answer 10

Passive transponders take the energy from the transmitter needed to respond back.
They have a very short range and the signal falls away quickly such at scanning products or books

Active transponders are battery powdered to respond back.
Can be read over a greater range such as at toll booths but have a limited lifetime as they are battery powered.