Properties of Materials
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Transcript Properties of Materials
Get the box of Stuff
Wood, steel, aluminum, melamine
Properties of Materials
Goal: Students will be able to
describe various physical
properties that materials have
Discussion
differentiate between chemical and
physical properties
At your tables list examples of chemical
and physical properties.
I will call on each table and make a list of
all the ones we can think of.
Chemical Properties
how a material interacts with another
material
“social” behavior
response to other matter (or lack of
response)
reactions
Chemical Properties
Examples:
burning
reaction with acid
reaction with water
corrosion/rusting/oxidation
others????
Physical Properties
characteristics it possesses by itself
“personal” traits
response to energy
(in and of itself)
Physical Properties
color
size
texture
melting point
boiling point
solubility
luster
density
magnetism
odor
viscosity
crystalline structure
Physical Properties
Electrical properties
conductor or insulator
Optical properties – response to light
index of refraction – bending of light
transparent – light passes through
translucent – some light passes through but no
distinct image
opaque – no light passes through
Physical Properties
Thermal properties – response to heat
conductivity
specific heat – how much energy it takes to
change temperature
thermal expansion – example: iron wire
demo
Mechanical Properties
subgroup of physical
response to force or stress
force – a push or pull
stress – force causing a deformation or
distortion (force per unit area)
Mechanical Properties
Examples
workability
malleability – can be flattened
ductility – can be drawn into wire
(stretched), bent, or extruded
Mechanical Properties
Examples
brittleness
breaks instead of deforming when stress is
applied
hardness
resistance to denting or scratching
Mechanical Properties
Examples
elasticity
ability to return to original shape after
being deformed by stress
rubber ball or piece of elastic
plasticity
retains new shape after being deformed by
stress
wet clay ball or piece of saran wrap
Some of the properties
At your tables you will find some signs
with different physical properties.
Go around between tables and answer the
questions on a separate piece of paper.
Index of Refraction
Question. What two materials here have a similar index of refraction?
(the three materials are glass, HDPE, and mineral oil)
Electrical conductivity
What materials here are non-conductive electrically?
(the materials are brass, copper coated steel, wax, glass and carbon fiber)
Hardness
Which material here is the hardest?
(Pine and Melamine)
Mechanical Properties
Examples
toughness
ability to absorb energy
resistance to fracture
strength
resistance to distortion by stress or force
several types: tensile, compressive,
torsional, bending, shear
Types of Stresses/Forces
Tension
pulling
examples: tug-of-war, slingshot
Compression
pushing together or squeezing
examples: bed springs, can crusher, bench vise
straight line = elastic region
curved line = plastic region
Ceramic or
glass
stress
metal
polymer
strain
City of Materials
http://www.cityofmaterials.com
General Classes of Materials
Polymers
Ceramics
Composites
Metals and Alloys
Metals and Alloys
Wood and Wood Products
Free write
On a piece of paper please describe
various physical and chemical properties
that material's have. If you can include
how you could test those physical
properties.