1: Introduction

Question 1

Define material

Answer 1

substances of which an object is composed or can be made. can be almost any solid that can be put in shape.

Question 2

which aren’t materials ? why ?
iron, helium, silica, h20, ethanol, wood, leather, concrete, polystyrene, epoxy, teflon, latex, diamond, boron nitride, fibreglass, co2, sodium chloride

Answer 2

helium
ethanol
air
co2

note - gases aren’t rly materials

Question 3

what is the subatomic structure ? does it play a role in a materials structure ?

Answer 3

arrangement of its internal components,
subatomic: electrons in atoms, interaction with nucleus
yes - the field of protons and electrons defines interactions w other elements.

Question 4

atomic structure refers to what ? what dimension range?

Answer 4

organization of atoms in molecules or crystals
0.1nm

Question 5

nanostructure refers to what ? what dimension range?

Answer 5

aggregates and particles of less than 100nm
100nm

Question 6

microscopic structure refers to what ? what dimension range?

Answer 6

related to large groups of atoms: phases
microscopic observation possible
100nm to several nm

Question 7

macroscopic structure refers to what ? what dimension range?

Answer 7

naked eye observable aspects
a few mm

Question 8

properties depend on what ?

Answer 8

properties depend on structure
ex: hardness vs structure of steel
-> harder as cooling rate increases

Question 9

processing can do what

Answer 9

change the structure
ex: structure vs cooling rate

Question 10

for example, how can the resistivity of copper be changed? how will it be affected ?

Answer 10

adding impurities increase resistivity

deforming increases resistivity

Question 11

describe transmittance; why does this occur ?

Answer 11

aluminum oxide may be transparent, translucent, or opaque depending on material structure
transparent: single crystal
translucent: polycrystalline, low porosity
opaque: polycrystalline, high porosity

Question 12

name 4 classes of materials

Answer 12

metal
polymer
ceramic
composite

Question 13

describe metallic bonding

Answer 13

in metals, electrons are free to move, they’re not bound to any atom - same applies to when they’re in bonds

this is why they’re good thermal/electrical conductors.
also not transparent to visible light.

Question 14

ceramics (and glasses) are a compound of what

Answer 14

compound between metallic and non-metallic element (often oxides, nitrides, carbides, ie metal w oxygen)

Question 15

are ceramics chemically reactive

Answer 15

not rly, if u put a strong acid in glass, nothing happens

Question 16

define ceramics. define glasses.

Answer 16

ceramics are crystalline, inorganic, non-metals

glasses are non-crystalline solids

Question 17

describe polymers (including molecular structure/composition)

Answer 17

very large molecular structure (often organic compounds, chemically based on carbon, hydrogen, and non-metallic elements)

low densities, cheap to put in shapes, can be flexible, properties often imaged by a pack of fibres

Question 18

describe composites composition

Answer 18

generally a combination of 2 or more different materials
can be at micro or macro scale

Question 19

which are composites

iron, helium, silica, h20, ethanol, wood, paper, leather, polystyrene, bread, stainless steel, epoxy, latex, glass, diamond, air, fibreglass, concrete, sodium chloride

Answer 19

wood, paper, leather, bread, latex, fibreglass, concrete

Question 20

note there are some property charts for each class at the end of slides.

Answer 20

.