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Properties of Matter 2.2 Physical Properties
Properties of Matter
2.2 Physical Properties
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 - Melting point– Conductivity - Boiling point– Malleability - Density– Hardness
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 CBoiling 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 / volumeSponge
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 Identify Materials
Step One: Decide which properties to test
Step Two: Test unknown sample
Step Three: Compare results with data reported for known materials
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
DistillationIs 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 ChangesPhysical 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
Quick Check
A material that is both malleable and conducts electricity well is most likely
a. Woodb.Icec. Metald.Motor oil
Quick Check
Which of the following is NOT an example of a physical property?
a. Flammabilityb.Malleabilityc. Conductivityd.Viscosity
Quick Check
Which of the following is a ten on the hardness scale?
a. Graniteb.Quartzc. Glassd.Diamond
Quick Check
Which of the following is an example of filtration?
a. Boiling sea water and collecting the clean gasb.Water dripping through ground coffee beans
to make coffeec. Crumpling a piece of paper d.Slicing a tomato in half
