The Atom

1
The Atom
An explanation on the Particle Theory of Matter
2
Democritus 460 BC

• Matter is the stuff that makes up everything in
  the world
• Matter is made of indivisible particles he called
  atomos.
• The first thinker on record to argue for the
  existence of an entirely
  empty "void".
• However others did not agree!

3
Aristotle 384 BC

• Matter is not particulate it is continuous.
• Matter is made up of the five elements
• Fire, Earth, Air, Water and Aether.
• However neither Democ.s or Aristotle's beliefs
  were backed up, since there was no physical
  evidence that supported eithers claims.

4
Alchemy

• both a philosophy and a practice with an aim of
  achieving ultimate wisdom as well as immortality,
  involving the improvement of the alchemist as
  well as the making of several substances
  described as possessing unusual properties
• Aristotles belief in the five elements formed
  the basis of alchemy and scientific progress in
  the field of chemistry was held back for nearly
  2000 years.

5
First, what type of experiment/demo can we do to
see if this idea of molecules actually exists?
6
What caused the can to collapse?

• When the can was heated the water turned to steam
  and the air inside became hot causing the
  molecules to move further apart. The expanding
  air was forced out of the can by the escaping
  steam. Less air molecules in the can create less
  air pressure.

7

• When the can was placed top down in the water the
  opening was covered. The greater air pressure on
  the outside of the can caused it to collapse.
• The explanation makes use of the particle theory
  of matter thus lending support to the existence
  of atoms.

8
Now how can we prove or disprove the PARTICLE
(Democ.) Theory of Matter?
9
What observations can we make that might support
or reject the idea that atoms exist?
10
Adding Volumes

• 500 mL 500 mL ?

11

• The particles (molecules) of one substance fill
  some of the spaces between the particles of the
  other substance thus, the resulting volume is
  less than the sum of the two.
• The particulate theory of matter
  (atoms/molecules) is supported because it
  provides an explanation.