DENSITY

There are three states of matter:

solid

liquid

gas

Density – the amount of matter that occupies space

Solids Liquids Gas

Molecules close together

Molecules spread out further

Molecules spread far apart

To determine density, you must divide the mass by the volume.

D = m÷v

Mass is measured in grams using a triple beam balance…

or a digital scale.

750 g

We can determine the mass of the box using the digital scale.

Volume of a regularly-shaped object can be measured using a ruler.

If the object has smooth sides where a ruler can be used to measure the length, width, and height, it is considered regular-shaped.

Volume = length x width x height

15 cm

5 cm

2 cm

V = l x w x h

V = 15 cm X 5 cm X 2 cm

V = 150 cm3

Determine the volume of the cube.

3 cm

V = l x w x h

V = 3 cm X 3 cm X 3 cm

V = 27 cm3

Volume of a liquid is measured in mL using a graduated cylinder or a beaker.

Objects that do not have smooth sides to measure are called irregular-shaped.

To measure the volume of these objects we use water displacement.

Water is put into a graduated cylinder and the volume of the water is measured. 10

20

30

40

50

The object is placed in the graduated cylinder.

10

20

30

40

50

The volume of the water and the object is determined.

The first volume is subtracted from the second volume.

40 mL – 29 mL = 11 mL

The volume of the object is 11mL.

Density does not depend on the amount of the substance.

The density of the block is 16 g/cm3

If it is cut in half, what happens to the density?

Density of block is 16 g/cm3

Density of block is 16 g/cm3

Sulfur Hexafluoride & Density

Sulfur Hexafluoride & Density

The density of water is 1g/mL.

If an object with a density of less than 1g/mL is placed in the water, it will float.

If an object with a density of greater than 1g/mL is placed in the water, it will sink.

Water Density = 1g/mL

Oil

Alcohol

DENSITY COLUMN

Can you give an estimation of the density of the alcohol and the oil?

Water

Density = 1g/mL

Oil

Alcohol

DENSITY COLUMN

The density of the oil is less than 1 g/mL. The density of the alcohol is less than the density of the oil.

Water Density = 1g/mL

Oil

Density = .96 g/mL

Alcohol

Density = .75 g/mL

DENSITY COLUMN

Estimate the density of the piece of wood.

The density of wood is .8 g/cm3.

Water Density = 1g/mL

Oil

Density = .96 g/mL

Alcohol

Density = .75 g/mL

DENSITY COLUMN

Estimate the density of the piece of ice.

The density of ice is .9 g/cm3.