Smart materials

Question 1

Piezoelectric material

Answer 1

Stimulus : movement, stress or electric
Appearance : Quartz , crystal , polymer
Stress or movement applied to a piezoelectric material produces an electric signal which is applied to the material which results in a change of shape.

Question 2

Practical example of Piezoelectric material

Answer 2

Speakers : The electric signal makes the metallic diaphragm move which creates sound.

Question 3

Litmus paper

Answer 3

Stimulus : pH

Characteristics : It reacts to the acidic or alkaline substances ,changing color to show which substance it is

Question 4

Uses of litmus paper

Answer 4

Science experiment to test for pH levels , soil testing and chemical testing in swimming pools

Question 5

Thermochromic pigment

Answer 5

Stimulus : Heat

Appearance : A powder that is added to many materials like fabrics and plastics

Question 6

Characteristics of Thermochromic Pigment

Answer 6

The pigments respond to the temperature around it and change colour as heat up or cool down.

Question 7

Uses of Thermochromic pigment

Answer 7

Children’s cutlery , clothing , novelty goods and overheating and cooling indicators.

Question 8

Shape memory alloy

Answer 8

Name : Nitinol
Stimulus : Heat or electricity
Appearance : Metal wire , varying in thickness

Question 9

Characteristics of Shape memory alloy

Answer 9

A shape can be programmed at a certain temperature , it can be deformed and it will return to its memory shape at that temperature

Question 10

Uses of Shape memory alloy in braces

Answer 10

It can be used for braces : It can be used as muscle wire . It will be stretched then , when an electric current passes through it , it will contract to 5 % of its length.

Question 11

Uses of Shape memory alloy

Answer 11

Frames for glasses , surgical stents and braces

Question 12

Photochromic pigment

Answer 12

Stimulus : UV light
Appearance : A pigment added to fabrics and plastics
Characteristics : They change color in the presence UV light . Once UV light is taken away they change back.
Uses : Colour changing nail varnish , clothing and beach and party products

Question 13

Example of e use of Photochromic pigment

Answer 13

In sunglasses , photochromic pigments darken when in the sun and return to clear glasses inside where there is little or no UV light. Disadvantage : Takes a full 2 minutes to return to normal which is inconvenient to the user.

Question 14

Poymorph

Answer 14

Name : Polycarprolactone
Stimulus : Heat
Characteristics : Easily mouldable and remouldable at low temperatures in water , non- toxic , reusable , fully biodegradable

Question 15

Uses of polymorph

Answer 15

Repairs , prototypes and can be used for household items for someone with arthiritis, jewellery