Properties of Matter
What is a physical property?
• A quality that of the material that can be seen
or measured without changing the
composition of the material (without changing
what its made of)
• Physical Properties:
– Viscosity
– Conductivity
– Malleability
– Hardness
- Melting point
- Boiling point
- Density
Examples of Physical Properties
• Viscosity : the tendency of a liquid to keep
from flowing, a liquid’s resistance to flowing.
– The greater the viscosity, the slower the liquid
moves
– Examples: honey and corn syrup
Discuss Viscosity
• Turn to your neighbor…in 30 seconds
–Choose two liquids to compare
–Explain which of the two has a higher
viscosity (which one resists flowing the
most)
–Listen as your neighbor does the same
thing (compares two new liquids)
Conductivity
• A materials ability to allow heat to flow
• Which spoon should you choose for stirring a
pot of soup heating on the stove?
Wooden spoon or metal Spoon?
Why did you choose the spoon that you did?
Malleability
• The ability of a solid to be hammered without
shattering
• Most metals are very malleable
• Other objects such as glass or fine china are
easily broken
Hardness
• One simple way to compare two materials is
to see which one will scratch the other one
• Which ever scratches the other is the harder
of the two
• A Diamond is the hardest known material and
a 10 on Mohs scale of hardness
Examples
Provide an example for each of the following
Something with high conductivity
Something easily malleable
Something that is softer than glass
Melting / Boiling Points
Melting point: the temperature at which a
substance changes from a solid to a liquid
For water normally occurs at 0o C
Boiling point: the temperature at which a
substance boils
For water normally occurs at 100o C
Density
Recall that density is the ratio of the mass of a
substance and its volume.
This ratio can be used to test the purity of a
substance
Density = mass / volume
Sponge
Brick
Using Physical Properties
Physical properties are used to identify a
material, to choose a material for a specific
purpose, or to separate the substances of a
mixture.
Using Properties to Choose Materials
The properties of a material determine which
materials are chosen for which uses.
Example: You would not want shoe laces made
of wood because they would not be flexible
Using Properties to Separate Mixtures
Some properties can be used to separate
mixtures
Filtration and Distillation are two common
separation methods
Filtration
Is a process that separates materials based on
the size of their particles
Example: Using a strainer to remove tea leaves
from a pot of tea
Distillation
Is a process that separates the substances in a
solution based on their boiling points
Example: on submarines sea water is boiled, the
clean gas collected and cooled for drinking
and the undrinkable compound left behind
*This works because the clean water has a
different boiling temperature than the
compounds
Recognizing Physical Changes
Physical change occurs when some of the
properties of a material change, but the
substances in the material remain the same.
Examples: crumpling a piece of paper and
heating butter in a pan
*Actions change the shape of the materials but
not their composition