1/10/11

Post date: Jan 10, 2011 5:42:56 PM

• • Questions on elements, compounds, and mixtures?

• Notes - Physical properties of matter

  • • 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

Notes - 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 9/1)