2. DensityDensity - the amount of mass per unit of- the amount of mass per unit of
volume.volume.
It can be expressed in the followingIt can be expressed in the following
formula.formula.●
The formula…The formula…
Density =Density = massmass
volumevolume
OrOr
D=m/vD=m/v
Mass usually expressed in gramsMass usually expressed in grams
Volume usually expressed in cm3 or liters, etc.
3. The “DMV” Triangle for
Volume, Mass, and
Density
Density = M
V
Volume = M
D
Mass = D x V
M
÷ ÷
D X V
4. Understanding DensityUnderstanding Density
●
In order to understand density, you must firstIn order to understand density, you must first
understand mass and volume.understand mass and volume.
●
●
MassMass--The amount of matter in an object.The amount of matter in an object.
(balance/scale)(balance/scale)
●
●
VolumeVolume-The amount of space occupied by an-The amount of space occupied by an
object. (ruler and formula or graduated cylinder)object. (ruler and formula or graduated cylinder)
●
●
So density is just the amount of matter in anSo density is just the amount of matter in an
object divided by the space that the objectobject divided by the space that the object
occupies.occupies.
5. ●
Density = mass / volumeDensity = mass / volume
●
●
Density compares mass to volume.Density compares mass to volume.
●
●
If you have any two components, you canIf you have any two components, you can
“figure out” mathematically the third“figure out” mathematically the third
component by substituting the numbers incomponent by substituting the numbers in
the formula. (D=m/v)the formula. (D=m/v)
●
●
6. ●
Density = mass / volumeDensity = mass / volume
●
●
To calculate density, substitute numbersTo calculate density, substitute numbers
(preferable from your data) for mass and(preferable from your data) for mass and
volume.volume.
●
●
You would use a scale or a balance to findYou would use a scale or a balance to find
mass, and you could either use a formula (lmass, and you could either use a formula (l
x w x h) or use a graduated cylinder to findx w x h) or use a graduated cylinder to find
volume.volume.
7. VolumeVolume
The formula for volume is …The formula for volume is …
V = l x w x hV = l x w x h
(volume = length x width x height)(volume = length x width x height)
Or,Or,
you could simply see how much water a solid oryou could simply see how much water a solid or
liquid object displaces in a graduated cylinder.liquid object displaces in a graduated cylinder.
8. ●
You can even determine the relativeYou can even determine the relative
densities of liquids by the layers that aredensities of liquids by the layers that are
formed when they are mixed, or what floatsformed when they are mixed, or what floats
upon what.upon what.
●
●
More dense substances sink.More dense substances sink.
●
●
Less dense substances float.Less dense substances float.
9. Density of WaterDensity of Water
●
The density of water is 1gram per milliliter,The density of water is 1gram per milliliter,
or D=1g/mlor D=1g/ml
●
●
Substances that are more dense thanSubstances that are more dense than
1g/ml will sink when placed in water.1g/ml will sink when placed in water.
●
●
Substances that are less dense than 1g/mlSubstances that are less dense than 1g/ml
will float when placed in water.will float when placed in water.
10. Density in SolidsDensity in Solids
Ice is less dense than water (which is why lakes
and ponds have a thin layer of ice covering in
winter, with water underneath)
Various rocks, woods, metals have a
characteristic density specific to that substance
12. Density in LiquidsDensity in Liquids
The more dissolved solids in a solution, the more
dense (such as ocean water)
Cold water in lakes tend to sink (this creates a
constant mixing of water, nutrients, and other
substances)
–Kinetic energy again!!
Denser layers to less dense layers…..
