Physical Properties
a measurable characteristic of a tangible (real) object.
Intensive Physical Property
one that does not depend on the size of the object; speed, density and hardness.
Extensive Physical Property
weight & electrical resistance are highly dependent on the size of the object.
What are the 5 Physical Properties?
hardness, density, luster, streak, and texture.
What are the 3 properties closely related to density?
Specific gravity and heft (weight)
Hardness
Intensive Physical Property; ability of a solid substance to resist permanent deformation when subjected to a compressive force.
How is relative hardness tested in geology?
Scratch test: Unknown sample is scratched with known samples.
What is the lowest mineral on Mohs Hardness Scale?
Talc
What is the highest mineral on Mohs Hardness Scale?
Diamond
How does the Mohs Hardness Scale work?
If a mineral is ranked lower, it can be scratched by higher ranked minerals. Higher ranked minerals cannot be scratched by lower ones.
Density (p)
an object is defined as the mass per unit volume.
Mass (m)
Represents the amount of matter that is present; measured in g or kg.
Formula for weight?
W = m * g
What does the symbol “g” mean?
Acceleration due to gravity (9.8 m/s²)
Volume (V)
Amount of 3-dimensional space that is occupies; expressed in liters, m³ or cm³
How is density calculated?
p = m/V
How is density used?
Used to estimate the actual composition of a material.
How is volume measured?
fluid displacement
Specific Gravity (Gs = ρ/ρw)
The density of an object relative to the density of water; if Gs < 1 = Floats; if Gs > 1 = Sinks
Heft
the perceived density obtained by holding the sample in your hand.
Luster
the way that light reflects, or doesn’t, from the surface of a material.
Streak
a small sample is dragged across a sample of an unglazed ceramic plate, leaving a streak of powdered material. The streak reveals the actual color of a mineral.
Texture
the shape, size, and arrangement of the component pieces.