1. Chapter 5 Density and Buoyancy
Grade 8 Science
Chapter 5
Density and Buoyancy

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Chapter 5.1
Density and Buoyancy

3. Density – The amount of mass in a certain volume of a substance
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Page 130
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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Page132
Density
Density can be described as the crowdedness of the particles in a substance

5. Density and States of Matter
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Page135
Density and States of Matter
In general, gases are less dense than liquids, and liquids are less dense than solids.

6. Density and States of Matter
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Page135
Density and States of Matter
The only way a pure substance can change density is to change state.
Solid gold is MORE dense than molten (liquid) gold.

7. Density: How are Mass and Volume Related?
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Chapter 5.2
Density: How are Mass and Volume Related?

8. Density – Mass vs Volume
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Page 137
Density – Mass vs Volume
Mass – The amount of particles in a substance
Volume – The amount of space occupied by a substance

9. Density – Mass vs Volume
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Page 137
Density – Mass vs Volume
Formula for Density:
Density (D) =
Mass (m)
Volume (V)

10. Density – Mass vs Volume
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Page 137
Density – Mass vs Volume
Example
The density of an object having a mass of 10g and a volume of 2 cm3 is…
D = = = 5 g/cm3
m g
V cm3

11. Buoyancy: The “Anti-Gravity” Force
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Chapter 5.3
Buoyancy: The “Anti-Gravity” Force

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Page 144
Why things Float…
Floating – when an object does not fall or sink, but suspends in a fluid

13. Gravity – force that pulls objects down
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Page 144
Buoyancy Force
Gravity – force that pulls objects down
Buoyancy – force that pushes objects up