1. Fluid Density
GCCE Physics Module – Saltwater Intrusion In Response To Sea Level Rise

2. What Is Density?

3. What Is Mass? Mass is the total amount of matter in an object
Measured in grams or kilograms
Mass can be found from weight using W=mg

4. What Is Volume?
Volume is the total amount of space an object occupies.
Measured in m3 or cm3

5. What Is Density?
Density is the total mass contained within a certain volume
Density is an intrinsic property. It is a property of a substance rather than a property of the amount of a substance. It always stays the same – no matter how much you have!
Substance
Density (g/cm3)
Helium
Air
0.0012
Propane
0.0018
Olive Oil
0.92
Water
1.00
Honey
1.36
Steel 8
Lead
11.3
Osmium
22.6

6. If steel sinks, why do ships float?
The air inside the hull counts as part of the ship’s volume.
The ship is made of heavy steel, but the ship’s overall density is less than water’s density. So- it floats!!

7. How do hot air balloons fly?
Hot air is less dense than cold air.
The overall density of the balloon and hot air is about the same as cold air.

8. What makes a submarine sink and surface?
A submarine has ballast tanks that can be filled with air or water.
In order to surface, pressurized air pushes water out of the ballast tanks- making it less dense than seawater.

9. What do we need to calculate density of fluids?
Remember the units:
kg/m3
g/cm3