1. Floating & Sinking Notes
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Floating & Sinking Notes

2. I. Buoyancy Ability to float
Archimedes’ principle – buoyant force = weight of fluid displaced

4. A solid block of steel sinks when placed in water
A solid block of steel sinks when placed in water. A steel ship with the same weight floats.

5. II. Density Mass per unit volume
“How much stuff in a specific amount of space”

6. 1. Examples: a) Mass = 50 g, Volume = 5 mL
b) Mass = 100 g, Volume = 10 cm3

7. 2. Comparing Densities Density of pure water = 1 g/mL
If an object is MORE dense, it will _____
If an object is LESS dense, it will _____
If it has EQUAL density, __________
sink
float
suspends

8. Density - Floating and Sinking
Changes in density cause a submarine to dive, rise, or float.

10. Comprehension Check

11. 1) Which has the greater density?
Coke
Diet Coke
They have the same density
Not enough information

12. 2) Assuming this is a tank of pure water… What is the density of Coke?
< 1 g/mL
> 1 g/mL
= 1 g/mL
Not enough information

13. 3) Which block has the higher density?
They’re the same
Not enough information

14. 4) Calculate the density: Mass = 10 g; Volume = 10 mL
1 g/mL
10 g/mL
100 g/mL
Not enough information

15. 5) Identify the unknown substance if Mass = 20 g; Volume = 20 mL
Gold
Air
Water
Methanol

16. 6) What property determines whether an object floats or sinks?
Weight
Density
Temperature
Speed

17. References http://www.pbs.org/wgbh/nova/lasalle/buoybasics.html