1. Density

2. One pound of feathers Or One pound of bricks?
Which weighs more?
One pound of feathers Or One pound of bricks?

3. DENSITY The amount of mass per unit of volume
Items with low density: feathers, marshmallows, pillows, etc.
Items with high density: rock, most metals, etc.

4. Mass The amount of matter in an object
Metric units are grams (g) or kilograms (kg)
Measured with a digital scale
NOT WEIGHT!

5. VOLUME The amount of space an object takes up Measured in 3 ways:
REGULAR SOLIDS
- Length x width x height (ruler) - in cm3
LIQUIDS
- use a graduated cylinder or beaker – in mL

6. VOLUME IRREGULAR SOLIDS Displacement (Archimedes Principle)
- add object to a known volume of water
- the amount the water rises is the volume of the object
- 1mL = 1 cm3

7. CONVERSIONS Mass: 1000 g = 1 kg Volume: 1000 mL = 1 L
cm3 = 1 m3
100 cm = 1 m
100 x 100 cm = 1 m2
100 x 100 x 100 cm = 1 m3

8. Density Problems

9. Density Problems Density is the mass per unit of volume
Units for density reflect both mass and volume – g/cm3 or kg/m3 are common
Use the magic triangle to solve problems

10. m D v Density Problems Horizontal line means divide
Vertical line means multiplication

11. Density Problems Example 1 – Solving for density
Find the density of a material if 230 grams of it has a volume of 15 cubic centimeters.
State what you know: mass = 230 g; volume = 15 cm3
Use the triangle: D = m ÷ v
Solve:
Finish with a statement: The material’s density is about 15.3g/cm3

12. Density Problems Example 2 – Solving for mass or volume
Find the volume of 1 kg of a material whose density is kg/m3.
State what you know: mass = 1 kg; density = 1260 kg/m3
Use the triangle: v = m ÷ D
Solve:
Convert: multiply m3 by to get cm3
Finish with a statement: The volume is about 794 cm3.

13. What is the density of the lead piece weighing 113.4g?
Ticket out of Class
What is the density of the lead piece weighing 113.4g?