or molecules that comprise a solid are packed close together
and are not compressible.
all solids have some thermal energy, its atoms do vibrate. However,
this movement is very small and very rapid, and cannot be observed
under ordinary conditions.
are the different types of solids?
four types of crystalline solids --
solids -- These substance appear as a single giant molecule
made up of an almost endless number of covalent bonds. An
example would be graphite. View
the 3-D structure of graphite).
solids are represented as repeating units made up of
molecules. An example would be ice.
the 3-D structure of ice.
solids are repeating units made up of metal atoms. The
valence electrons in metals are able to jump from atom to
Amorphous solids do not have a definite melting point or regular
repeating units. An amorphous solid is a solid in which there
is no long-range order of the positions of the atoms unlike
those in crystalline solids. An example of an amorphous solid
is window glass. In addition many polymers such as polystyrene
are amorphous.Amorphous solids can exist in two distinct states,
the 'rubbery' state and the 'glassy' state. The temperature
at which they transition between the glassy and rubbery states
is called their glass transition temperature or Tg.
Note on Solids: While no mass at all is an impossibility,
aerogels seem to come pretty close. Aerogels are the lightest
solids and have a density of 1.9 mg per cm3 or 1.9 kg/m3 (526.3
times lighter than water). Sometimes called frozen smoke, aerogels
are open-cell polymers with pores less than 50 nanometers in
are the properties of a Liquid?
have a definite volume, but are able to change their shape by
are similar to solids in that the particles touch. However the
particles are able to move around.
are able to touch, the densities of liquid will be close to
that of a solid.
liquid molecules can move, they will take the shape of their
are the specific properties of liquids?
--The resistance of a liquid to flow is called its viscosity
Tension -- The result of attraction between molecules of a liquid
which causes the surface of the liquid to act as a thin elastic
film under tension. Surface tension causes water to form spherical
-- The pressure that a solid or liquid exerts when it is in
equilibrium with its vapor at a given temperature.
Point -- when vapor pressure = atmospheric pressure.
are the properties of a Gas?
no definite volume or shape. If unconstrained gases will spread
out indefinitely. If confined they will take the shape of their
container. This is because gas particle have enough energy to
overcome attractive forces. Each of the particles are well separated
resulting in a very low density.
-- There are several excellent interactive java applets which
Model for an Ideal Gas
dimensional gas of hard spheres
Motion for Gas
is the fourth state of matter?
state of matter is plasma. Plasma is an ionized gas, a gas into
which sufficient energy is provided to free electrons from atoms
or molecules and to allow both species, ions and electrons,
to coexist. In effect a plasma is a cloud of protons, neutrons
and electrons where all the electrons have come loose from their
respective molecules and atoms, giving the plasma the ability
to act as a whole rather than as a bunch of atoms. Plasmas are
the most common state of matter in the universe comprising more
than 99% of our visible universe and most of that not visible.
Plasma occurs naturally and makes up the stuff of our sun, the
core of stars and occurs in quasars, x-ray beam emitting pulsars,
and supernovas. On earth, plasma is naturally occurring in flames,
lightning and the auroras. Most space plasmas have a very low
density, for example the Solar Wind which averages only 10 particles
per cubic-cm. Inter-particle collisions are unlikely - hence
these plasmas are termed collisionless.
a fifth state -- Bose Einstein?
of the atoms into a single quantum state is known as Bose condensation
or Bose-Einstein condensation is now considered a 5th state
scientists have discovered the Bose-Einstein condensate, which
can be thought of as the opposite of a plasma. It occurs at
ultra-low temperature, close to the point that the atoms are
not moving at all. A Bose-Einstein condensate is a gaseous superfluid
phase formed by atoms cooled to temperatures very near to absolute
zero. The first such condensate was produced by Eric Cornell
and Carl Wieman in 1995 at the University of Colorado at Boulder,
using a gas of rubidium atoms cooled to 170 nanokelvins (nK).
such conditions, a large fraction of the atoms collapse into
the lowest quantum state, producing a superfluid. This
phenomenon was predicted in the 1920s by Satyendra Nath Bose
and Albert Einstein, based on Bose's work on the statistical
mechanics of photons, which was then formalized and generalized