Salinity, ppm

0 3e415000

0 .25 .5 .75 1 1.25 1.5 1.75 2 2.25 2.5 2.75 3 3.25 3.5

00

.025

.05

.075

.1

.125

.15

.175

.2

.225

.25

.275

.3

.325

.01 km.005 km

t = 0OBLEYML Thu Jun 24 2010

Fluid DensityGCCE Physics Module – Saltwater Intrusion In Response To Sea

Level Rise

What Is Density?

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

What Is Volume?

• Volume is the total amount of space an object occupies.

• Measured in m3 or cm3

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 0.00018

Air 0.0012

Propane 0.0018

Olive Oil 0.92

Water 1.00

Honey 1.36

Steel 8

Lead 11.3

Osmium 22.6

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!!

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.

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.

What do we need to calculate density of fluids?

• Remember the units: – kg/m3

– g/cm3