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