1/12/2010
Post date: Jan 11, 2010 8:9:4 PM
Bell Activity: Give a complete description of the machine on the front table.
Physical properties
Characteristics that can be observed without changing the identity of the substance
Help identify a substance
Can be observed or measured
Color
Melting point - temperature at which a substance will melt or freeze
Boiling point - temperature at which a substance will evaporate or condense
Strength - resistance to breaking
Hardness - resistance to bending or flexing
Magnetism - ability to be attracted to a magnet
Conductivity - ability to conduct electricity
Density - ratio of mass to volume of a substance
Help determine uses for a substance
Density
Is mass / volume
Is a physical property
Is constant for a given substance
Can be used to identify a material
Is DIFFERENT FROM WEIGHT!!!!!
People use "light" and "heavy" for weight and for density
Many would say a brick sinks in water because it is "heavy" -- actually, it is because the brick is more dense than water. A boat, which is much "heavier" than a brick, will float in water because it is less dense than water.
Density Lab due Thursday (lab can be found in "handouts" section)