**Density**

**Density**

Defined: The mass of a substance per unit volume

History of Density

Archimedes' Principle

Density Equation

Which is most Dense?

Density Tower

D = mass = m

volume v

Directly Proportional

Inversely Proportional

Density

Density

to Mass

to Volume

D = mass = m

volume v

Volume changes

Mass stays the same

Mass changes

Volumes stays the same

Word Problems

Iron has a known density of 7.87 g/cm3. What is the mass of a 2.50 cm3 piece of iron?

d = m

What do we know?

d = density =7.87 g/m3

v = volume = 2.50 cm3

m = ?

Mass = Volume x Density = v x d = 4.87 g x 2.50 cm3 = 1,217.5 g

v

cm3

Another Word Problem

A beaker contains 10 ml of liquid. The beaker has a mass of 15 grams when empty. The beaker plus the liquid has a mass of 49 grams. What is the density of the liquid in g/ml?

d = m

What do we know?

v = volume = 10 ml

m (of liquid) = (mass of liquid + beaker) – mass of beaker = 49 g – 15 g = 34 g

d = ?

d = m = 34 g ÷ 10 ml = 3.4 g

v

v ml

A. Density is DIRECTLY proportional to mass. This means that if volume remains constant, (does not change), density increases as mass increases. And density decreases as mass decreases.

B. Density is INVERSELY proportional to volume. This means that if mass remains constant (does not change), density decreases as volume increases. And as volume decreases density increases.

Directly Proportional

Inversely Proportional