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Question 1

Describe Ceramics

Answer 1

Hard and nonmetallic substances which are resistant to heat

Divided into glass and clay, and clay is divided into
1) Brick 2) Porcelian 3) China

Question 2

describe how glass is special

Answer 2

a special type od ceramic not made of clay, instead sand is melted then cooled and solidified

Question 3

describe properties of metal

Answer 3

hard strong shiny suctile malleavle good conductors
can be made into alloys to strengthen or electroplated to improve looks and resist corrosion

Question 4

describe polymers and their properties

Answer 4

a long chain of moelcules made up of many monomers
strong, good insulators unreactive waterproof
can be moulded into shaped and can have rigid or flexible forms

Question 5

what is a composite material

Answer 5

a mixture of two or more materials to produce a material with improved properties

made up of a reinforcement and matrix such as concrete
cement is matrix
water and aggregate is reinforcement

Question 6

describe matrix and reinforcement in steel reinforced concrete

Answer 6

matrix is concrete
reinforcement is steel rod

Question 7

describe plywood

Answer 7

matrix is lignin and reinforcement is cellulose fibres

wood is stronger along the grain than across the grain

layers glued at right angles to increase the strength in all directions

Question 8

solid glass can be better than clay cermaics for building houses and homes due to higher compressive strength. so why not?

Answer 8

glass blocks are transparent so the walls can be seen through

Question 9

What is a nanoparticle sizes

Answer 9

are tiny particles consisting of only a few hundred atoms, they are named because their size is measured in nanometer
between 1nm to 100nm

Question 10

Which is larger, nanoparticles, atoms molecules or cells?

Answer 10

nanoparticles are larger than atoms and molecules but smaller than cells

Question 11

Size of a silver atom is 0.3 nm, size of silvernanoparticle is 90nm, cal how many times larger silver nanoparticle is to a silver atom

Answer 11

no of times larger=
90nm/ 0.3nm= 300

Question 12

uses of nanoparticles

Answer 12

1. titanium dioxide nanoparticles are used as sunscreen
   -TiO absorbs UV rays which could cause skin cancer
   -TiO nanoparticles are transparent so they cannot be seen on rhenskin
   -TiO nanoparticles have greater surface area to vol ratio so smaller amounts can br used

2) Silver nanoparticles can kill bacteria, in some cultures water was stored in silver containers to keep it fresh