TOPIC: Lab SkillsAIM: How do we determine density?

DO NOW: Explain how layers exist in cappuccino.

Layers exist in cappuccino

because ________________________________________________________________________________

DensityThe measure of

the amount of mass that is in each unit of volumemass per unit volume

Triple beam balance for mass

Graduated cylinder for volume of a

liquid

Metric ruler for volume of a

solid

InstrumentsInstruments neededneeded

To measure To measure densitydensity

or

Grams/mlor

Grams/cm3

Box A has a greater density than Box B

Because Box A has a greater mass (more matter/ molecules)

in the same volume

A B

Warm air rises b/c it is less dense than cold air which

sinks.

1 gm/mL

Density of water

Why will an objectfloat or sink?

FLOATS when the density of the object is LESS than the density of the liquid.

SINKS when the density of the object is GREATER than the density of the liquid.

Less dense than water

More dense than water

Which is more dense?Salt

water

Warm water rises b/c it is less dense than cold water which

sinks.

Each pure substance has it’s “own

density” no matter what size it is.

Density Facts

cut it in half

So……If I Cut the substance in half each half would still have the same

density

M = 20 gm V = 10 mLDensity = 20/10 = 2 gm/mL

Cut the block in half

M = 10 gm V = 5 mLDensity = 10/5 =

2gm/mL

wood

plastic

rubber

copper

Density = Mass

Volume

D

M

V

AIM:

D

M

VMass = Density X Volume

Volume = Mass / Density

Denisty = Mass / Volume

1. What is the density of a metal block that has a mass of 525 gm and a volume of 50 cm3?

Example #1:

•D = m v•D = 525 gm 50 cm3

•D = 10.5 gm/cm3

Silver =

10. 5 g/cm3

What is the

block made

of?

The mass of a marble is 8.8 gm. It has a volume of 2 mL. What is it’s density?

Example #2

•D = m v•D = 8.8 gm 2 mL•D = 4.4 gm/mL

Example #1

M = 45gm

D = 20.1 gm/mL

Volume = ? D

M

V

•V = M D•V = 45 gm 20.1 gm/mL•V = 2.2 mL

Will this

objectfloat orsink inwater?Why?

•Sink•It’s density is greater than the density of water (1 gm/mL)

Example #2D = 3.5

gm/mL V = 1.6 mL

Mass = ? D

M

V

•M = D x V•M = 3.5 gm/mL x 1.6mL

•M = 5.6 gm