1. Notes: Density

2. Q: Which place has a higher density of people living in 1 square mile, New York city or Antartica?

3. Density: The amount of mass per unit of volume of material

4. Density = mass
volume
Units
Density --- g/cm3
Mass – g
Volume -- cm3

5. Sample Problem: A piece of metal has a mass of 90 g and its volume is 5 cm3. What is the density of the metal?
D = g
5 cm3
= g/ cm3

6. How do you find the mass of an object? Duh! Use a triple beam balance!
Measuring Density: To measure the density of a material or object you first need to measure both its mass and its volume.
How do you find the mass of an object? Duh! Use a triple beam balance!
How do you find the volume of an object? It depends!

7. Measuring the volume of a regular shaped object:
Volume = L x W x H
Ex. Volume of box
Volume = 6x4x5
= 120 cm3

8. Measuring the volume of an irregular shaped object: Use graduated cylinder and measure the displacement
Vol. of marble = 30 – 23
= 7 ml or
7cm 3

9. Density of water = 1 g/cm3
If an object has a:
--- density less than 1, then it will float in water
-- density more than 1, it will sink in water