The density is the ratio of mass (stuff that

makes up an object) and its volume (the

amount of space that stuff takes up). The

more mass an object has in a give amount of

space, the more dense it is. To say it another

way, the more con”densed” the matter is, the

more dense it is!

m2 m2

Which is more dense?

Density can be calculated using the following formula:

Whereas, D =

M =

V =D = MV

mass

volume

density

M

D V

M

D V

Density = MV

Volume = MD

Mass = D x V

Example: A wooden block with a mass of 80.0 g is 8 cm long, 3 cm wide, and 4 cm high. Calculate the wooden block’s density.

Length =

Width =

Height =

8.0 cm

3.0 cm

4.0 cm

8.0 cm

3.0 cm

4.0 cm

Volume = L x W x H

Volume = 8.0 cm x 3.0 cm x 4.0 cm = 96.0 cm3

Mass =

Volume =

Density =

80.0 g96.0 cm3

80.0 g

96.0 cm3

0.833 g/cm30.8 g/cm3

10th space

Step 2

Wait for all of the water to flow out of the overflow can into the beaker positioned below the spout.

Step 3

Take the water in the beaker and pour it into the graduated cylinder. Be sure not to spill any!

Step 4

Read the volume of the water in the graduated cylinder. This should equal the volume of the mineral originally placed in the overflow can.

Determining the volume of an irregular objectStep 1

Place the object in the overflow can.

Overflow Can

Does changing the size of a pure substance change its density?

Density = 16 s per 8 sDensity = 2 s per

Does changing the size of a pure substance change its density?

Density = 8 s per 4 sDensity = 2 s per

Does changing the size of a pure substance change its density?

Density = 4 s per 2 sDensity = 2 s per

What happens to the density of a material when you break it into pieces?

D = m/v

M = 2,000 g

V = 1,000 mL

D = ? g/mL

D = m/v

M = 2,000 g

V = 1,000 mL

D = ? g/mL

Answer: The density does not change !!!

M = 24 g

V = 12 mL

D = ___ g/mL

M = 14 g

V = 7 mL

D = ___ g/mL

M = 10 g

V = 5 mL

D = ___ g/mL

What happens to the density, volume and mass of most materials when you heat them?

D = m/v

M = 10 g

V = 1 mL

D = ____ g/mL

D = m/v

M = 10 g

V = 1 mL

D = ____ g/mL

D = m/v

M = 10 g

V = 1 mL

D = ____ g/mL

D = m/v

M = 10 g

V = 2 mL

D = ____ g/mL

D = m/v

M = 10 g

V = 1 mL

D = ____ g/mL

D = m/v

M = 10 g

V = 3 mL

D = ____ g/mL

D = m/v

M = 10 g

V = 1 mL

D = ____ g/mL

D = m/v

M = 10 g

V = 5 mL

D = ____ g/mL

→ No change

→ Increases

→ Decreases

An object will sink in a fluid with

a lower density and float in a

fluid with a greater density.

0.8 g/mL

1.0 g/mL

1.5 g/mL

2.0 g/mL

D= 2.5 g/mL

D= 0.75 g/mL

D = 1.0 g/mL

D= 1.8 g/mL

D = 1.0 g/mL

D = 0.9 g/mL

D = 0.2 g/mL

Finding the Percentage BELOW the Surface

Step 1

Divide the density of the object by the density of the fluid it is floating in.

Ex. Ice = 0.92 g/mL

Water = 1.0 g/mlStep 2

Multiply your answer from Step 1 by 100. This equals the percent found BELOW the surface.

Ex. 0.92 x 100 = 92% This means 92 percent of an ice cube is found below the surface of water.

8.0 % Above

92.0 % Below

If the density of ice is 92% of the density of water, than 92% is found BELOW the surface. How much is found above?

Water

Ice

Try this example!

An object with a density of 1.3 g/mL is

placed in a cup of pure water (density of

water is 1.0 g/mL). What percentage of

the object is found below the surface?