Density is defined as mass per unit volume. It is a measure of how tightly packed and how heavy the molecules are in an object. Density is the amount of matter within a certain volume. Which has the greatest density? Why?

Density Notes

Which one is more dense?

Demonstration: People in a square

How about this: Which square is more dense?

Which one is more dense?

Now which one is more dense?

Two related terms of Density• 1- Mass- the amount of matter in an object;

it is how much stuff an object has

• Unit used for mass is grams (g) and kilograms (kg)

• How measured: scale

Which has more mass? Why?

2 term related to Density

• Volume- the amount of 3-dimensional shape an object occupies

• Can be measured by:

Volume = L * W * H (box or cube)

Graduated Cylinder (for a liquid) (beaker)

Displacement (irregularly shaped object)

Units for volume: cm3, in3, Liters (L), mL

Volume

1) Which has the greatest volume? Figure it out.

2) Which has the greatest volume?

Calculating Density

The formula for density is:

Density = Mass

Volume

Units: g/mL, g/cm3, kg/L

Units for density g/cm3 or g/mL

Formula: M = mass V= volume D = density

M = D x V V = M / D D = M / V

1) Find the mass of the object

2) Find the volume of the object

3) Divide : Density = Mass - Volume

To find density:

Set up your density problems like this:

Givens: Unknown:

Formula: D = M / V Solve

Ex. If the mass of an object is 35 grams and it takes up 7 cm3 of space, calculate the density.

• Calculate the volume of a liquid with a mass of 10 g and whose density is 2 g/mL. - givens:– unknown:– formula for unknown: – plug in values and solve.

To find the density1- Find the mass of the

object- use a scale

2- Find the volume of the object-

3- Divide Density = Mass

Volume

Density Units

• Density- the amount of mass in a given volume.

• Density = mass / volume

• Units- kg/L or kg/m3

g/mL or g/cm3

• The density of gold is approximately 19 g/cm3

1) How much would 2 cm3 of gold weigh?

2) What is the mass of 1 cm3 of gold?

• A liquid has a density of 2 g/mL. What exactly does this mean?

• A liquid has a density of 1.5 g/mL.

1)What is the mass of 1 mL of this liquid?

2) What is the mass of 2 mL of this liquid?

3) What is the mass of ½ a mL of this liquid?

Proof that water and ice have different densities

1) Find the mass of the object

2) Find the volume of the object

3) Divide : Density = Mass - Volume

To find density:

Ex. If the mass of an object is 35 grams and it takes up 7 cm3 of space, calculate the density.