2. Learning Target: Be able to explain how an object’s density is related to its mass and volume both mathematically (quantitatively) and in words (qualitatively). Learning Outcome : Complete “Density Lab”

3.  An object’s density is related to the amount of matter or “stuff” (mass) contained in a corresponding unit of volume.  Density is a physical property of matter.  It is an Intensive property meaning density of a material does not change depending on the amount measured (see first slide).

4.  Density is a ratio (mass/volume) with SI dimensions [kg]/[m 3 ]  For our class, we will mostly use units of g/cm 3

5. Substance ρ [kg]/m 3 Air0.0013 * Ice0.917 Water1.00 (Sometimes used as Reference) Aluminum (Al)2.70 Iron (Fe)7.86 Gold (Au)19.3 *at 0 o C and 1 atm Pressure In general, density decreases as a substance moves from solid  liquid  gas Do you notice any exceptions above?

6.  Density is related to buoyancy because objects less dense than another (i.e. water) will float.  To calculate a relative density, just divide the substance you are analyzing by a reference: pH 2 O= 1.00kg/m 3 pIce=.917kg/m 3.917/1.00 =.917 If the substance is less than the reference (ratio is < 1) it will float.