Physical Properties
of Matter
 Physical Property – any characteristic of a
material that can be observed or measured
without changing the composition (makeup) of
the substances in the material.
 These properties are used to identify a material or
chose which material to use for a certain task.
 One must look at more than one physical property
to make their decision.
Examples of physical
properties
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Viscosity
Conductivity
Malleability
Hardness
Melting and Boiling Point
Density
Viscosity
 Viscosity – the tendency of a liquid to
keep from flowing (its resistance to
flowing)
 Thick liquids have a high viscosity.
 Thin, runny liquids have a low viscosity.
 Viscosity is usually decreased when the
liquid is heated.
Conductivity
 Conductivity – material’s ability to allow
heat to flow
 Metals conduct heat well…called
conductors.
 If conducts heat well, usually conducts
electricity well.
Ouch!
Malleability
 Malleability – the ability of a solid to be
hammered without shattering.
 Most metals are malleable.
 If not malleable, then we call substances brittle
because it breaks when hammered (like ice).
Hardness
 Compare hardness by
scratching.
 If a material can scratch
another, then it is harder than
the other material.
 Stainless steel can scratch
copper. Thus, steel is harder
than copper.
 A diamond is hardest known
material.
Melting and Boiling Points
 Melting Point –
temperature at which a
substance changes from
solid to liquid
 Boiling Point –
temperature at which a
substance changes from
a liquid to a gas
Density
Density – ratio of a substance’s mass to its
volume
Density = mass/Volume
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Mass – g
Volume - mL or cm3 or cc
Density – g/mL or g/cm3
Densities
Material
Water at 4 C
Water at 20 C
Gasoline
Magnesium
Copper
Gold
Ice at 0 C
Air
Helium
Density (gm/ cm3)
1.0000
0.998
0.70
1.7
8.3-9.0
19.3
0.92
0.001293
0.000178
Separating Materials via
Physical Properties
 Filtration – separating materials
based on the size of their particles
(like straining spaghetti or tea)
 Distillation – process that
separates the substances in a
solution based upon boiling points.
Distillation is done by heating a liquid
until it boils, capturing and cooling the
hot vapors, then collecting the
condensed vapors. As a result the
impurities (or unwanteds) are left
behind in the 1st container.
Physical Change
 Physical change – occurs when some of the
properties of a material change, but the substances in
the material remain the same.
Examples:
 Cutting hair (hair is still hair even though it looks different)
 Slicing a tomato
 Ironing a shirt
 Freezing water into ice
 Some physical changes are reversible, which means
that you can take the substance back to the original.
 Ice melts and can become ice again
 When you cut hair off, you can’t put it back.