based on the laws of physics that describe mass, energy, force, light, heat, electricity and other physical phenomena
physical properties
subgroup of physical properties. Describes the material's ability to resist forces
mechanical properties
describe the setting reactions as well as the decay or degradation of materials
chemical properties
effects the materials having on a living tissue
biologic properties
amount or mass of a material in a given volume
density
two physical properties of materials
boiling and melting points
measure of a liquid's tendency to evaporate and become a gas
vapor pressure
rate of heat flow through a material
thermal conductivity
measure of amount of thermal energy that a material can hoard
heat capacity
amount of energy needed to raise the temperature of one unit of mass of that material by 1 degree C
specific heat capacity
amount of energy required to melt a material
heat of fusion
amount of energy required to boil a material
heat of vaporation
measure of this change in volume in relation to the change in temperature; shrink or contract
coefficient of thermal expansion
process of heating and cooling, and the accompanying oening and closing of the gap
percolation
new amalgam filling will hurt when it is touched with a metal form. result of electricity flowing from the fork to the amalgam and through the pulp
galvanic shock
material's ability to flow
viscosity
doing this brings material into intimate association with the surface so that chemical and micromechanical bonding can occur
wetting
measured by scientific instruments that press a special tip into the surface of the test material
hardness
measures how deep a steel ball will sink in a soft material
durometer measurements
wear resistance
abrasion resistance
not too hard and not too soft.. just right
Goldilocks principle
amount of a material that dissolves in a liquid such as water
solubility, like sugar
materials absorbing water
water sorption
weight or load applied to an object
force
force divided by the area on which the force has been applied
stress
a measure of push or pull that changes the shape of an object
elasticity
change in length divided by the original length
strain
slope of a graph of stress versus strain
modulus of elesticity
when a stress is removed and the object returns to its original length, the initial change in length is called
elastic deformation
permanently stretched out
plastic deformation or permanent deformation
The point on the stress-strain plot at which the line starts to curve and plastic deformation begins is called
elastic limit, proportional limit, or yield point
exceeding the strength of the spring
ultimate strength
test is a tensile test
ultimate tensile strength
test is a compressive test
ultimate compressive strength
Types of stress
compression
tension
shear
torsion
bending
mechanical property that is the ratio of the strain in the direction of stress to the strain in a direction perpendicular to the stress
poisson's ratio
ability to absorb energy and not become deformed
resilience
the energy absorbed up to the failure point on the stress-strain diagram is the
toughness of materials
measure of the enrgy required to fracture a material when a crack is present
fracture toughness
many things fail after being stressed repetitively for a long time
fatigue
small change in shape that results when an object is under continuous compression
creep
slow decrease in force over time
stress relaxation
stress increases around defects
stress concentration
a drop of water on a popsicle is an example of
a. poor wetting (low contact angle)
b. good wetting (high contact angle)
c. good wetting (low contact angle)
d. poor wetting (high contact angle)
c. good wetting (low contact angle)
the tightening of a guitar string is an example of which of the following stresses?
a. compression
b. torsion
c. shear
d. tension
d. tension
The modulus of elasticity is an indication of what property of a material?
a. resilience
b. strength
c. stiffness
d. tension
c. stiffness
T/F
Cooled materials will contract, and heated materials will expand. A measurement of this change in volume in relation to change in temperature is called the coefficient of thermal expansion.
Both statements are true
When a stress is induced in a material that is greater than the material's yield strength, the stress is _______ proportional to the strain, and the material does not return to its original shape
a. always
b. no longer
c. equally
d. none of the above
b. no longer
Which formula defines the modulus of elasticity?
a. stress/strain
b. stress^2/strain
c. strain/stress
d/ 2 x stress/strain
a. stress/ strain
An example of a physical property is
a. density
b. strength
c. stiffness
d. setting reaction
a. density
A twisting force is termed
a. compression
b. shear
c. tension
d. torsion
e. bending
d. torsion
The ability of a material to dissolve in liquid is termed
a. viscosity
b. water sorption
c. solubility
d. wetting
c. solubility
Elasticity is an example of which of the following properties?
a. physical
b. mechanical
c. chemical
d. biologic
b. mechanical
The rate of heat flow through a material is referred to as
a. heat of fusion
b. coefficient of thermal expansion
c. heat capacity
d. thermal conductivity
d. thermal conductivity
Jennifer is a practicing hygienist who goes to a nearby restaurant each day for lunch. She often orders a cola with ice and a bowl of homemade soup. As she eats and drinks her composite restoration and tooth structure are expanding and contracting at diff
b. coefficient of thermal expansion
Fingernail polish remover has "solvent' properties, as it will remove the polish from our fingernails. Another property polish remover has is its tendency to evaporate. Fingernail polish remover can be said to have.
a. high vapor pressure
b. low vapor pre
a. high vapor pressure
_______ is the force used to condense an amalgam in a preparation
compression
A hardened cement having "low" ______________ can firmly hold a patient's gold crown in place for years in a wet environment
solubility
_____ is the term given to the increase of stress around defects within an object
stress concentration