Chemical Collisions, from
Cambridge Micro Software,
manages to combine all the
qualities you expect from a
first-class CAL package (including
the price - only £15.95).
The program, which comes
on an 80-track disc, is aimed at
15 to 16 year-olds studying
basic chemical changes, and at
17 to 18 year-olds working on
the mathematics of reaction
kinetics.
It shows the effects, at the
molecular level, of combining
two gases.
Each set of randomly-moving
particles has its own colour, and
if two particles of different
colours collide with sufficient
energy, a new white particle is
formed. Simple in concept, the
program does much more than
this.
It not only takes into account
elapsed time, temperature and
initial molecular concentrations
(all under user-control), but also
continuously updates the data it
is accessing, so that the chance
of an effective collision is
determined by an interaction of
all three factors.
In addition, the element of
randomness gives slightly differ
ing results with each reaction.
The result is that the program
can be run several times using
the same initial parameters, and
the mean result calculated, just
as in real experiments.
Numerical counts of all
collisions, effective collisions
only, and particle populations
can be displayed at any time
during a reaction, and plotted as
graphs or bar charts to show
how the relative particle con
centrations have changed with
time.
A reaction can be stopped at
any point so that data can be
analysed in detail.
User-definable controls allow
colours of particles to be
changed (essential with a mono
chrome monitor), function keys
to be used for storing sets of
commands, and adjustments to
be made to the monitor setting.
The quality of the graphics
and speed of animation are well
above average and the documentation
is also very well done,
with excellent teaching sugges
tions.
Chemical Collisions has been
designed throughout with the
user in mind, and in operation it
provides a flexible and very
convincing simulation of
chemical reactions and diffusions
which no book or even
video can hope to compete with.
1st December 1985
