1. DENSITY
Mr. Bantay - Oceanography

2. LAB OVERVIEW: Density
• The Earth is
structured
on the basis
of DENSITY

3. What is Density?
• Density is described as the amount of matter
within a given amount of volume.
• Simply, it’s the amount of molecules in a given
amount of space.
• As a result, substances with a higher density will
settle to the bottom and substances with lower
density will rise.
• The size of the substance will NOT affect
DENSITY.

4. Density
• Examples:
a) Cold water/air b) Warm water/air

6. Let’s Practice
• Pick up worksheet and calculator.
• Answer questions.

7. How do we find the density of a
substance?
1. You need to know the MASS.
-simply use a scale or triple beam balance to
obtain its mass (in grams).

8. 2. You need to
know its
VOLUME.

9. The OBJECTS

10. The OBJECTS

11. FORMULA?
L x W x H
Length = 6cm

12. FORMULA?
L x W x H
Length = 6cm
Height = 4cm

13. FORMULA?
L x W x H
Length = 6cm
Height = 4cm
Width = 2cm

14. FORMULA?
L x W x H
Length = 6cm
Height = 4cm
Width = 2cm

16. So, the VOLUME of this object is
48 cm3

17. The OBJECTS

18. Find VOLUME

19. The METHOD
-40mL
-35mL
-30mL
-25mL
-20mL
-15mL
-10mL
-5mL

20. 1. Note the water level
-40mL
-35mL
-30mL
-25mL
-20mL
-15mL
-10mL
-5mL

21. 2. Place the object in liquid
-40mL
-35mL
-30mL
-25mL
-20mL
-15mL
-10mL
-5mL

22. -40mL
-35mL
-30mL
-25mL
-20mL
-15mL
-10mL
-5mL

23. -40mL
-35mL
-30mL
-25mL
-20mL
-15mL
-10mL
-5mL
3. Note difference in water level

24. The water level changed 15mL
We can say the rock displaced 15mL
-40mL
-35mL
-30mL
-25mL
-20mL
-15mL
-10mL
-5mL

25. It gets better!
-40mL
-35mL
-30mL
-25mL
-20mL
-15mL
-10mL
-5mL

26. Volume of our rock…

27. •Can’t use the volume formula (no edges)…
•Can’t use the displacement technique….

28. Steps…
First find the MASS:
Find the mass of the container = “a”
Fill container with water and obtain the mass of both = “b”
Find mass of JUST WATER = “b” – “a”
Now let’s find the VOLUME:
Simply find the volume of the container.
Use density formula: D = mass/volume

29. Density
• Today, you will be finding the DENSITY OF
several substances:
1. Water
2. A block of wood
3. A rock called granite (a rock that makes up
the Earth’s continental crust)
4. A rock called basalt (a rock that makes up
the Earth’s oceanic crust)
5. 5 minerals: pyrite, galena, quartz, fluorite,
topaz

30. THE EQUATION
D =M
V

31. THE TRICK

32. Cover up the one you want to solve for!

33. Let’s solve for VOLUME.
“M over D”
is remaining
so we divide!

34. Let’s solve for Density.
“M over V”
is remaining
so we divide!

35. Let’s solve for Mass.
“D next to V”
is remaining
so we
multiply!

36. Density solutions…
Water = 1 g/mL3
Wooden Block = .50 g/cm3
Granite = 2.7 g/cm3
Basalt = 3.0 g/cm3