Chemistry Reference
In-Depth Information
Fig. 1.3
Half-spheres of Magdeburg: Guericke's demonstration of air pressure
those half-spheres apart by using all their power. This power was necessary to
overcome the pressure of air on both empty half-spheres!
Theories of atomism and the structure of matter
. These theories have their origin
in interpretations of the Greek philosophy schools. Two schools of thought existed:
one school around Democritus and Leucippus believed that repeated partition of a
piece of matter had an end and that matter is built of undividable particles, called
atoms (Greek: atomos, undividable). This conception assumed discrete particles
and empty space around them - therefore today it is called the
discontinuity
hypothesis.
Aristotle and other philosophers thought that a repeated partition of matter does
not lead to an end. Especially the mental impossibility of an empty space, which
separated one particle from another - the “horror vacui” - convinced them of a
continuously structured matter: the
continuity
hypothesis was born. Due to the wide
influence of the Aristotelian school the continuity idea was taught everywhere,
Democritus's atoms disappeared for almost 2,000 years.
After Torricelli disproved the idea of the “horror vacui” in a macroscopic way
and the vacuum became imaginable, Gassendi transferred this knowledge on the
existence of a vacuum to the submicroscopic level. He broke away from the
Aristotelian conception and took up Democritus's idea: the atoms and the empty
space between the atoms are the big principles of nature [
6
]. After a disruption of
2,000 years scientists could now take the discontinuity hypothesis as a basis to think
about smallest particles and the structure of matter. In 1808, Dalton formulated his
atomic hypothesis that there are as many kinds of atoms as kinds of elements and
