grade 8 science chapter 5 density and buoyancy chapter 5 density and buoyancy
TRANSCRIPT
Grade 8 ScienceGrade 8 Science
Chapter 5
Density and Buoyancy
Chapter 5
Density and Buoyancy
Chapter 5.1Chapter 5.1Chapter 5.1Chapter 5.1
Density and Buoyancy
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DensityDensityDensityDensity
Density – The amount of mass in a certain volume of a substance
A “heavy” substance has a high density
A “light” substance has a low density
Density – The amount of mass in a certain volume of a substance
A “heavy” substance has a high density
A “light” substance has a low density
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DensityDensityDensityDensity
Density can be described as the crowdedness of the particles in a substance
Density can be described as the crowdedness of the particles in a substance
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Density and States of Density and States of MatterMatterDensity and States of Density and States of MatterMatter
In general, gases are less dense than liquids, and liquids are less dense than solids.
In general, gases are less dense than liquids, and liquids are less dense than solids.
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Density and States of Density and States of MatterMatterDensity and States of Density and States of MatterMatter
The only way a pure substance can change density is to change state.
The only way a pure substance can change density is to change state.
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Solid gold is MORE dense than molten
(liquid) gold.
Chapter 5.2Chapter 5.2Chapter 5.2Chapter 5.2
Density: How are Mass and
Volume Related?
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Density – Mass vs VolumeDensity – Mass vs VolumeDensity – Mass vs VolumeDensity – Mass vs Volume
Mass – The amount of particles in a substance
Volume – The amount of space occupied by a substance
Mass – The amount of particles in a substance
Volume – The amount of space occupied by a substance
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Formula for Density:
Density (D) =
Formula for Density:
Density (D) =
Density – Mass vs VolumeDensity – Mass vs VolumeDensity – Mass vs VolumeDensity – Mass vs Volume
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Mass (m)Volume (V)
Example
The density of an object having a mass of 10g and a volume of 2 cm3 is…
D = = = 5 g/cm3
Example
The density of an object having a mass of 10g and a volume of 2 cm3 is…
D = = = 5 g/cm3
Density – Mass vs VolumeDensity – Mass vs VolumeDensity – Mass vs VolumeDensity – Mass vs Volume
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m 10gV 2cm3
Chapter 5.3Chapter 5.3Chapter 5.3Chapter 5.3
Buoyancy: The “Anti-Gravity”
Force
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Why things Float…Why things Float…Why things Float…Why things Float…
Floating – when an object does not fall or sink, but suspends in a fluid
Floating – when an object does not fall or sink, but suspends in a fluid
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Buoyancy ForceBuoyancy ForceBuoyancy ForceBuoyancy Force
Gravity – force that pulls objects down
Buoyancy – force that pushes objects up
Gravity – force that pulls objects down
Buoyancy – force that pushes objects up
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