Aim: What is Density?Do Now:

In your notebooks, explain what you think determines an objects density?

And then, try to explain how you would find an objects density (formula/steps/process)?

I. Density: The amount of matter in a specific volume.

- A physical property of matter.- Measured in g/cm3 or g/ml. - Every object has it’s own

unique density.

D = MV

** Density of an object remains the same no

matter how many pieces it’s broken into

**

Using the one density formula you can rearrange the variables to solve for

mass and volume.

Density MassVolume=Density

Mass =

Density x

Volume

MassVolume=Density

DM

V

II. Buoyancy vs. Density

• Buoyancy is an objects ability to float in water.

- determines if an object will sink, float or remain neutral in water.

What does neutrally buoyant look like?

• Which color liquid is most dense?

• Which color liquid is least dense?

• Where would a metal sphere with a density of 3.0g/ml land?

5.4 g/ml -

4.3 g/ml - 2.9 g/ml -

1.3 g/ml -

Example: Compare the density of H2O (water) to the density of an ice cube.

THINKAn ice cube floats in H2O because

it has a density that is…a) Equal to the density of waterb) Greater than the density of waterc) Less than the density of waterd) None of the above

III. Density of Water and Ice

- As water freezes it expands. (increases volume)

- This make ice less dense than water

Ice always floats the same in water

no matter the size or shape.

ice ice

IV. Frozen Lakes

- Water is most dense at 4oC in the Liquid phase. Just before it freezes into ice.

ICE

00C

40C

-100C air temp.

Why does a steel ship float in water?

Densities in grams / cm3D (water) = 1.0 g / cm3D (wood) = 0.8 g / cm3D (steel) = 7.8 g / cm3D (lead) 11.3 g / cm3D (air) .0012 g / cm3Answer:

A ship has a steel shell that is hollow inside. The volume is mostly air. The ship and air together have a density less

than water.

• Closure:

From the back table, top bin; take a density review worksheet from the top bin to work on in class with your partner using your notes.