DENSITY RULES

All pieces of the SAME material (no matter what the size) should have the density. When a piece breaks, the density of each piece is the same as the original. SAME Constant relationship density Why? The atoms are still packed the same size

How to change the density of a material?

The only way to change the density of a material is to change the way the atoms “pack”. The easiest way to do this is to change its temperature or pressure.

a. Temperature

a. Temperature As an object is heated, it expands (volume increases) and the atoms become less packed. Therefore the object becomes less dense.

When an object is cooled, it contracts (come together) and the atoms become more packed. Therefore, the object becomes more dense.

Indirect Relationship Density Temperature As temperature increases, density __________ Decreases

a. Pressure Pressure – the force applied to a unit area of surface Volume – decreases Mass – remains the same Density - increases

As pressure increases, density ____________ Increases Direct Relationship As pressure increases, density ____________ Increases

3. Density of Water 1g/cm3 Density of water is: It is most dense at 3.98o C because the water expands above and below this temperature ESRT Page 1

4. Less dense objects will on top of more dense objects 4. Less dense objects will on top of more dense objects. The dense objects will be on the bottom and the less dense on top. float

Graphing and Density If volume is on the independent variable (X-axis) and mass is the dependent variable (Y-axis), then the slope of the line will indicate the ________ of the material being graphed. density

Slope = density = mass Slope = rise run = Density volume Mass (g) Volume (cm3) Slope = rise run = mass volume = Density

Density of Water Slope = rise run = mass volume = Density 3 3 = Mass (g) Volume (cm3) Slope = rise run = mass volume = Density 3 3 = = 1g/cm3

More Dense Water Mass (g) Less Dense Volume (cm3) run volume