Factors Affecting Density. Temperature As the temperature of most substances increases –Atoms move...

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Factors Affecting Factors Affecting Density Density
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Transcript of Factors Affecting Density. Temperature As the temperature of most substances increases –Atoms move...

Page 1: Factors Affecting Density. Temperature As the temperature of most substances increases –Atoms move faster and spread apart. –Expansion increases the volume.

Factors Affecting DensityFactors Affecting Density

Page 2: Factors Affecting Density. Temperature As the temperature of most substances increases –Atoms move faster and spread apart. –Expansion increases the volume.

TemperatureTemperature

• As the temperature of most substances increases– Atoms move faster and spread apart.– Expansion increases the volume which decreases the density

because the mass remains the same.

Colder Warmer

Page 3: Factors Affecting Density. Temperature As the temperature of most substances increases –Atoms move faster and spread apart. –Expansion increases the volume.

PressurePressure

• Solids– At great depths

below Earth’s surface there is extremely high pressure from the overlying rocks.

– Minerals are compressed• Volume decreases.• Density increases

Page 4: Factors Affecting Density. Temperature As the temperature of most substances increases –Atoms move faster and spread apart. –Expansion increases the volume.

Fluids Fluids (Particularly gases such as the atmosphere)(Particularly gases such as the atmosphere)

• As pressure decreases, gases expand.• This results in an increase in volume.• Density decreases

Page 5: Factors Affecting Density. Temperature As the temperature of most substances increases –Atoms move faster and spread apart. –Expansion increases the volume.

Shape and SizeShape and Size

• If the temperature of a material remains constant, the size and shape will not affect it’s density.

• The mass and volume change proportionately.

Al of these Aluminum objects have the same density

Page 6: Factors Affecting Density. Temperature As the temperature of most substances increases –Atoms move faster and spread apart. –Expansion increases the volume.

Phases of MatterPhases of Matter

• For most substances particles are most closely packed in the solid phase.

• Most materials are densest in their solid phase.

Page 7: Factors Affecting Density. Temperature As the temperature of most substances increases –Atoms move faster and spread apart. –Expansion increases the volume.

Water is unusual because it is densest as a liquid.

• As liquid water cools, it contracts and becomes denser until it reaches a temperature of 4o Celsius (3.98o C).

• As water cools from 3.98o C to 0o C it expands, becoming less dense.

Page 8: Factors Affecting Density. Temperature As the temperature of most substances increases –Atoms move faster and spread apart. –Expansion increases the volume.

This has profound implicationsThis has profound implications

• Ice floats resulting in– icebergs floating in

the ocean

– Lakes freezing from the top down.

Page 9: Factors Affecting Density. Temperature As the temperature of most substances increases –Atoms move faster and spread apart. –Expansion increases the volume.

Expanding water in pipes and cracks in rocks Expanding water in pipes and cracks in rocks will cause them to break apartwill cause them to break apart

Page 10: Factors Affecting Density. Temperature As the temperature of most substances increases –Atoms move faster and spread apart. –Expansion increases the volume.

The reason for this unusual property is the The reason for this unusual property is the nature of the water molecule.nature of the water molecule.

(1) The molecule’s shape is asymmetrical and polarized.(a) One side is positively charged(b) The other side has a slight

excess of negative charged.

(2) When water is in the liquid state(a) Molecules are moving around.(b) Because of polarity some

molecules are slightly attracted to one another

(c) The are closer together than in most liquids.

Page 11: Factors Affecting Density. Temperature As the temperature of most substances increases –Atoms move faster and spread apart. –Expansion increases the volume.

When Water FreezesWhen Water Freezes

• Bonding hydrogen atoms are shared between adjacent water molecules.

• An orderly, hexagonal pattern results.• The open honeycomb-like crystal structure contrasts

with the more closely packed molecules in liquid water.

Page 12: Factors Affecting Density. Temperature As the temperature of most substances increases –Atoms move faster and spread apart. –Expansion increases the volume.

Density is a concept Density is a concept important to geology.important to geology.

A few examples include:A few examples include:

Page 13: Factors Affecting Density. Temperature As the temperature of most substances increases –Atoms move faster and spread apart. –Expansion increases the volume.

Plate Tectonics – Density is a factor for …Plate Tectonics – Density is a factor for …

Motions associated with plate boundaries

Behavior of seismic wavestraveling through Earth’s interior

Continental Drift

Volcanic and Earthquake Activity

Page 14: Factors Affecting Density. Temperature As the temperature of most substances increases –Atoms move faster and spread apart. –Expansion increases the volume.

Mantle ConvectionMantle Convection

Page 15: Factors Affecting Density. Temperature As the temperature of most substances increases –Atoms move faster and spread apart. –Expansion increases the volume.

Behavior of PollutantsBehavior of Pollutants

Oil SpillsOil Spills

Page 16: Factors Affecting Density. Temperature As the temperature of most substances increases –Atoms move faster and spread apart. –Expansion increases the volume.

Density of Pollutants Affects FlowDensity of Pollutants Affects Flow

Page 17: Factors Affecting Density. Temperature As the temperature of most substances increases –Atoms move faster and spread apart. –Expansion increases the volume.

Sediments Flowing into the OceanSediments Flowing into the Ocean