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Get the box of StuffGet the box of StuffWood, steel, aluminum, melamine Wood, steel, aluminum, melamine
Properties of Properties of MaterialsMaterials
Goal: Students will be able to Goal: Students will be able to describe various physical describe various physical
properties that materials haveproperties that materials have
DiscussionDiscussion
differentiate between chemical and differentiate between chemical and physical propertiesphysical properties
At your tables list examples of chemical At your tables list examples of chemical and physical properties.and physical properties.
I will call on each table and make a list I will call on each table and make a list of all the ones we can think of. of all the ones we can think of.
Chemical PropertiesChemical Properties
how a material interacts with another how a material interacts with another materialmaterial
““social” behaviorsocial” behavior
response to other matter (or lack of response to other matter (or lack of response)response)
reactionsreactions
Chemical PropertiesChemical Properties
Examples:Examples: burningburning reaction with acidreaction with acid reaction with waterreaction with water corrosion/rusting/oxidationcorrosion/rusting/oxidation others????others????
Physical PropertiesPhysical Properties
characteristics it possesses by itself characteristics it possesses by itself (in and of itself)(in and of itself)
““personal” traitspersonal” traits
response to energyresponse to energy
Physical PropertiesPhysical Properties
colorcolor sizesize texturetexture melting pointmelting point boiling pointboiling point solubilitysolubility
lusterluster densitydensity magnetismmagnetism odorodor viscosityviscosity crystalline crystalline
structurestructure
Physical PropertiesPhysical Properties Electrical Electrical propertiesproperties
conductor or insulatorconductor or insulator
Optical Optical properties – response to lightproperties – response to light index of index of refraction refraction – bending of light– bending of light transparenttransparent – light passes through – light passes through translucenttranslucent – some light passes through but – some light passes through but
no distinct imageno distinct image opaqueopaque – no light passes through – no light passes through
Physical PropertiesPhysical Properties
ThermalThermal properties – response to properties – response to heatheat
conductivityconductivity
specific heat – how much energy it takes specific heat – how much energy it takes to change temperatureto change temperature
thermal expansion – thermal expansion – example: iron wire example: iron wire demodemo
Mechanical PropertiesMechanical Properties
subgroup of physicalsubgroup of physical
response to force or stressresponse to force or stress forceforce – a push or pull – a push or pull
stressstress – force causing a deformation or – force causing a deformation or distortion (force per unit area)distortion (force per unit area)
Mechanical PropertiesMechanical PropertiesExamplesExamples
workabilityworkability malleabilitymalleability – can be flattened – can be flattened ductilityductility – can be drawn into wire – can be drawn into wire
(stretched), bent, or extruded(stretched), bent, or extruded
Mechanical PropertiesMechanical PropertiesExamplesExamples
brittlenessbrittleness breaks instead of deforming when stress breaks instead of deforming when stress
is appliedis applied
hardnesshardness resistance to denting or scratchingresistance to denting or scratching
Mechanical PropertiesMechanical PropertiesExamplesExamples
elasticityelasticity ability to return to original shape after ability to return to original shape after
being deformed by stress being deformed by stress rubber ball or piece of elasticrubber ball or piece of elastic
plasticityplasticity retains new shape after being deformed retains new shape after being deformed
by stress by stress wet clay ball or piece of saran wrapwet clay ball or piece of saran wrap
Some of the propertiesSome of the properties
At your tables you will find some At your tables you will find some signs with different physical signs with different physical properties. properties.
Go around between tables and Go around between tables and answer the questions on a separate answer the questions on a separate piece of paper.piece of paper.
Index of RefractionQuestion. What two materials here have a similar index of refraction?
(the three materials are glass, HDPE, and mineral oil)
Electrical conductivityWhat materials here are non-conductive electrically?
(the materials are brass, copper coated steel, wax, glass and carbon fiber)
HardnessWhich material here is the hardest?
(Pine and Melamine)
Mechanical PropertiesMechanical PropertiesExamplesExamples
toughnesstoughness ability to absorb energy ability to absorb energy resistance to fractureresistance to fracture
strengthstrength resistance to distortion by stress or resistance to distortion by stress or
forceforce several types: tensile, compressive, several types: tensile, compressive,
torsional, bending, sheartorsional, bending, shear
Types of Types of Stresses/ForcesStresses/Forces
TensionTension pullingpulling examples:examples: tug-of-war, slingshottug-of-war, slingshot
CompressionCompression pushing together or squeezingpushing together or squeezing examples:examples: bed springs, can crusher, bench visebed springs, can crusher, bench vise
stress
strain
Ceramic orglass
metal
polymer
straight line = elastic regioncurved line = plastic region
General Classes of General Classes of MaterialsMaterials
PolymersPolymers
CeramicsCeramics
CompositesComposites
Metals and AlloysMetals and Alloys
Metals and AlloysMetals and Alloys
Wood and Wood Wood and Wood ProductsProducts
Free writeFree write
On a piece of paper please describe On a piece of paper please describe various physical and chemical various physical and chemical properties that material's have. If properties that material's have. If you can include how you could test you can include how you could test those physical properties. those physical properties.