Chapter 2 Section 2 Physical Properties

A characteristic that can be observed or measured without changing the composition of the substances in a sample Viscosity Conductivity Malleability Hardness Melting Point Boiling Point Density

Viscosity How well a liquid resists flowing Honey – High Viscosity Water – Low Viscosity Importance Motor oil in a car helps lubricate engine parts

Conductivity The ability to allow heat to flow Conductors – A high conductivity Metals Insulators – A low conductivity Wood Which is safe in an electrical socket Metal or Plastic Fork?

Malleability The ability to be hammered without shattering Gold is Malleable Ice Cubes are NOT Malleable A solid that shatters when struck is considered brittle

Hardness Harder materials will scratch softer ones You can scratch glass with metal because the metal is harder than the glass You CANT scratch glass with you finger nail because the glass is harder Diamond is the hardest know material

Melting & Boiling Points Melting Point Temperature at which a substance changes from a solid to a liquid Boiling Point Temperature at which a substance boils

Density Ratio of an object ’ s mass to it ’ s volume Density = Mass/Volume Used to determine purity Silver has a density of 10.5 If a coin has a density of 9.9, then it is likely NOT silver

Using Physical Changes Physical Properties are used to identify a material, to choose a material for a specific purpose, or to separate the substances in a mixture

Using Physical Properties To Identify Crime scenes can use it to ID a car in a hit and run based on the paint chips To Choose Materials Nylon shoelaces work much better than wooden ones

To Separate Mixtures Filtration A process that separates materials based on the size of their particles Distillation Process that separates the substances in a solution based on their boiling points Separate water from salt-water

Recognizing a Physical Change Occurs when some of the properties of a material change, but the substances in the material remain the same Freezing, Boiling, or Melting Water Crumpling Paper MOST can be reversed Slicing Tomato Wrinkled Shirt