DENSITY

• Amount of matter (mass) in a given volume • Solids: units are g/cm3

• Liquids: units are g/mL• *1 mL = 1 cm3

DENSITY

• Which one has a greater density? Why?

• They both have the same volume, but the brick has a greater mass.

• Its mass per volume is higher, so the brick has a higher density.

DENSITY

• Which one has a greater density? Why?

• They both have the same mass, but the grape has a lower volume.

• The grape has more mass in less volume, so it has a higher density than the Styrofoam.

COMPARING DENSITY

• Italian salad dressing is made of 3 main components: oil, vinegar, and spices.

• We can see 3 “layers” in a bottle of dressing.

• It separates because the layers have different densities. Which layer is the most dense? Which is the least dense?

OIL

VINEGAR

SPICESHighest Density

Lowest Density

COMPARING DENSITY

• Lower density objects will float on top of higher density objects

OIL

VINEGAR

SPICESHighest Density

Lowest Density

CALCULATING DENSITY

• The two factors that affect density are mass and volume

CALCULATING DENSITY

• The two factors that affect density are mass and volume

CALCULATING DENSITY

• !"#$%&' = )*++

,-./)0

• 12345" = )*++

607+89:

• 5;$$ = !"#$%&' × 12345"

CALCULATING DENSITYIf a sample of jet fuel has a mass of 8.30 g and a volume of 10.3 mL, what is its density?

!"#$%&' =5;$$

12345"

= =8.30 B

10.3 5D

D = 0.806 g/mL

Water has a density of 1.0 g/mL. Will jet fuel float or sink when mixed with water?Float

CALCULATING DENSITYThe density of salt is 2.16g/cm3. What is the mass if you have a cube of salt with a volume of 400 cm3?

5;$$ = !"#$%&' × 12345"

Mass = 2.16g/cm3 × 400cm3

Mass = 864 g

CALCULATING DENSITYDiamonds have a density of 3.51g/cm3. A 1 carat diamond has a mass of 0.2 grams. What is the volume of a 1 carat diamond in milligrams? 12345" =

)*++

607+89:

1 =0.2B

3.51B/H5I

v = 0.057 cm3

CALCULATING DENSITY

What is the density of a 250 g rectangular box that is 10 cm long, 5 cm wide and 2 cm in height?mass = 250 gvolume = l x w x h

= 10cm x 5cm x 2cm= 100cm3

!"#$%&' =5;$$

12345"= =

250B100H5I

D = 2.5g/cm3

CALCULATING DENSITY

How do we calculate the volume of irregular shaped objects, like a rock? Use displacement: the amount of space an object takes up when placed in a fluid. (Like adding ice to water)

Final volume – Initial volume = Displacement

The amount of displacement is equal to the volume of the solid object.

CALCULATING DENSITY

How do we calculate the volume of irregular shaped objects, like a rock? Use displacement: the amount of space an object takes up when placed in a fluid. (Like adding ice to water)

Final volume – Starting volume = Displacement

The amount of displacement is equal to the volume of the solid object.

CALCULATING DENSITYA beaker contains 50mL of water. When a rock is dropped in the beaker, the water level rises to 77mL. If the rock has a mass of 89g, what is the density of the rock?

Mass = 89g

Volume = final – initial = 77mL – 50mL = 27mL

!"#$%&' =5;$$

12345"= =

89B

275D

D = 3.3g/mL