States of Matter
9 All matter has thermal energy because the
States of Matter
The Kinetic Molecular Theory
particles that make up matter are constantly
moving.
9 It
I iisn’t
’ hard
h d to imagine
i
i that
h the
h particles
i l off a
liquid or a gas are moving.
liquid
gas
States of Matter
States of Matter
9 But what about a solid object like a pencil?
9 All objects have thermal energy (heat)
Solids certainly don’t seem to be moving.
because their particles are moving.
The hotter an object
gets the faster the
particles move
The colder an object
gets the slower the
particles move
9 The pencil itself may not be moving, but the
particles that make it up are vibrating.
States of Matter
The Kinetic
Molecular Theory
describes the motion
of atoms as heat is
added, and matter
changes from a solid,
to liquid, and finally a
gas.
States of Matter
9 The Kinetic Molecular Theory states that all
matter is made up of small particles that are in
constant motion.
9 We measure the energy of these movements as
the temperature of the substance.
9 The more energy a substance has, the more
molecular movement there will be, and the
higher the perceived temperature will be.
1
States of Matter
States of Matter
9 Atoms and molecules that have relatively small
9 Solids have the least energy, and the
amounts of energy (and movement) will interact
strongly with each other, while those that have
relatively
l ti l high
hi h energy will
ill interact
i t
t only
l slightly,
li htl
if even at all, with others.
How does this affect the
States of Matter?
States of Matter
individual molecules are “frozen” in place
by the attractive forces between the
molecules (intermolecular forces).
9 In the Liquid State, the energy of the system
is increased, and the rigid structure of the
solid state is broken. Molecules move past
one another, but remain relatively close due
to intermolecular forces.
States of Matter
9 Gases are formed when the energy in the
Assumes
shape &
volume of
container
Definite
Volume &
shape of
container
Definite
Shape and
Volume
Physical
Properties
system exceeds all of the attractive forces
between molecules. Thus ggas molecules
have little interaction with each other
beyond occasionally bumping into one
another. In the gas state, molecules move
quickly and are free to move in any
direction, spreading out long distances.
States of Matter
Let’s take a look at some interactive links …
1. http://www.visionlearning.com/library/module_vie
wer.php?mid=120
2. http://cwx.prenhall.com/petrucci/medialib/media_
portfolio/text_images/031_ChangesState.MOV
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