1 of 16

Mass, Volume, & Density

Mass- The amount of matter in an object.

Volume-The amount of space that something occupies.

Density-The property that describes the ratio of mass to volume.

2 of 16

What is density?

  • 1. Density is the measurement of the compactness of an object.
  • 2. Density is a property that is determined by the ratio of a substance’s mass to its

volume.

  • 3. Mass is how much matter is contained in an object.
  • 4. Volume is how much space something occupies.

​

3 of 16

Density

  • All substances (solids, liquids, or gases) have unique densities.
  • Density is a GREAT way to identify unknown substances!

​

4 of 16

Which one is more dense?

People in a square

  • Which square is more dense?
  • Volume? Mass?

A B

A B

5 of 16

Which one is more dense?

  • Now which one is more dense? Volume? Mass?

A B

6 of 16

What is density?

  • Density = mass OR mass ÷ volume.

volume

​

  • Units for density: g/cm3 OR g/ml .

​

ALWAYS REMEMBER UNITS!

7 of 16

CAREFUL!

  • Cutting an object into pieces WILL NOT change its density. You have not changed the particle compaction in any way!
  • Example: If the density of a piece of American red oak wood is .74 g/cm3. If you cut the piece of wood in half, the density would NOT decrease by two, IT WOULD STAY THE SAME!

8 of 16

What can float on water?

  • Density of water is 1.0 g/ml
  • If the density is greater than 1.0 g/ml, then the object will sink in water.
  • If the density is less than 1.0 g/ml, then the object will float in water.

​

9 of 16

Liquid Layers

  • If you pour together liquids that don’t mix and have different densities, they will form liquid layers.
  • The liquid with the highest density will be on the bottom.
  • The liquid with the lowest density will be on the top.

10 of 16

Formula List

Name

Formula

Possible Units

Example

Density

D=M/V

g/mL or g/cm3

30 g/mL

Mass

M=D x V

g or kg

50 g

Volume

V=M/D

mL or cm3

25 mL

11 of 16

Let’s try a density problem together

  • Frank has a paper clip. It has a mass of 9g and a volume of 3cm3. What is its density?

​

​

​

​

12 of 16

Now, try these on your own.�Choose 2

  • 1.Alicia has a watch. It has a mass of 4g and a volume of 2cm3. What is the density of the watch?
  • 2.A cube made of plastic has a mass of 45g and measures 6cm a side, will it sink or float?
  • 3.Mia has a wallet. It has a mass of 15g and a volume of 5cm3. What is the density of the wallet?
  • 4.A block has a mass of 20g and measures 2cmX4cmX2cm, will it sink or float?

​

​

​

13 of 16

Answers

  • 2 g/cm3
  • .208 g/cm3 FLOAT
  • 3 g/cm3
  • 1.25 g/cm3 SINK

​

​

14 of 16

Practice�Choose 2

  • 1. A gold-colored ring has a mass of 18.9 grams and a volume of 1.12 mL. Is the ring pure gold? (The density of gold is 19.3 g/mL.)
  • 2. What volume would a 0.871 gram sample of air occupy if the density of air is 1.29 g/L?
  • 3. A cup of sugar has a volume of 237 mL. What is the mass of the cup of sugar if the density is 1.59 g/mL?
  • 4. A crumpet recipe calls for 175 grams of flour. According to Julia Child's data, the density of flour is 0.620 g/mL. How many mL of flour are needed for this recipe?

15 of 16

Answers

  • 16.8 g/mL
  • .675 L
  • 376.83 g
  • 282.25 mL

​

​

​

​

16 of 16

Sink or Float?

  • From their density values, decide whether each of the following substances will sink or float when placed in sea water, which has a density of 1.025 g/mL.

Gasoline 0.66 g/mL Asphalt l.2 g/mL

Mercury 13.6 g/mL Cork 0.26 g/mL