Transcript States of Matter Density Buoyancy Viscosity NOTES!!!

States of Matter
Density
Buoyancy
Viscosity
NOTES!!!
What is Matter?


Anything that has mass and takes up
space
So pretty much anything you can imagine
– from the air we breathe, to water we
drink, to the sun and all the stars.
4 States of Matter
 Solid
 Liquid
 Gas
 Plasma
Solid State
 Lowest
energy form of matter
 Molecules do not change
position
 Definite Shape
 Definite Volume
Liquid State
 Molecules
can move around
each other
 Definite volume
 Takes shape of container
Gas State
 Molecules
move freely and
separate from one another
 No definite shape
 No definite volume
Plasma
 Most
common state of matter (in
universe)
 Highest energy form of matter
 Made up of ionized gas molecules
(atoms breaking apart due to high
heat/energy)
DENSITY
Two Ways to Measure Matter..
 Mass
 Volume
Density is..
A
property that relates mass
and volume (combines them)
 Density = mass/volume
 OR
 Density equals mass per unit
volume (g/cm3)
Density affects…
 Hardness
(resistance to scratching)
 Elasticity (ability to stretch and
return)
 Brittleness (likelihood to shatter)
 Malleability (ability to made into thin
sheets)
 Tensile Strength (how much force
before breaking)
Density of Fluids
 Tend
to be less dense than solids
 Molecules move around each
other
 Do not “stack” easily
 Water is an exception – ice is less
dense than water (due to
structure of water)
Density Math
 The
density of a material can be
determined by dividing the mass by
the volume
 Ex.
What is the density of a 400 g
block that has a volume of 16 cm3?
 Answer:
400/16 = 25 g/cm3
Conversions
Sometimes the mass is given in a unit
other than grams.
 Or the volume is given in a unit other than
mL.
 Ex. What is the density of a block that
weighs 2.5 kilograms and has a volume of
40 cm3?
 The mass must be converted into grams
(g)
 Answer: 2500/40 = 62.5 g/cm3

Turning things around
 If
you are given the density and
volume of a substance, you can
determine its mass.
 Ex. What is the mass of a block that
has a density of 3 g/cm3 and a
volume of 40 cm3?
 D=m/v, re-arranged, m=Dv
 Answer: 3 X 40 = 120g
Turning things around.. Again..
 The
same can be applied to
volume..
 D=m/v, re-arranged, v=m/D
Note…
A
cm3 is equivalent to a mL.
Specifically, mL is used for
volume of gasses and liquids
and cm3 is used for the volume
of solids.
BUOYANCY
Definition
 The
measure of upward
pressure a fluid exerts on an
object
Buoyancy is…
 Determined
by density
 The
denser the fluid, the more buoyant
force it applies
 Ruled
 The
by Archimedes’ Principle
force exerted on an object by a
liquid is equal to the mass of the fluid
displaced by that object
Displaced
 To
move something from its
usual place
Therefore…
 If
buoyant force is greater than
the mass of the object, the object
FLOATS
 If buoyant force is less than the
mass of the object, the object
SINKS
Neutral Buoyancy
 Is
achieved when the mass of the
object is EQUAL to the mass of
the liquid displaced by that
object.
 The object floats exactly in the
position it is placed.
VISCOSITY
Definition
 Measure
of a material’s
resistance to flow
(how hard it is to pour)
Viscosity is determined by…
 Size
of liquid molecules
 Shape of liquid molecules
 Temperature of liquid
Therefore…
A
thick substance is described as
being very viscous
 Ketchup, syrup (cold)
 Motor oils have different grades
based on viscosity (10W-40, 10W30)