Chapter One

1.1 SURFACE ANALYSIS

We interact with our surroundings through our five senses: taste, touch, smell, hearing, and sight. The first three require signals to be transferred through some form of interface (our skin, taste buds, and/or smell receptors). An interface represents two distinct forms of matter that are in direct contact with each other. These may also be in the same or different phases (gas, liquid, or solid). How these distinct forms of matter interact depends on the physical properties of the layers in contact.

The physical properties of matter are defined in one form or another by the elements present (the types of atoms) and how these elements bond to each other (these are covered further in Section 2.1). The latter is referred to as speciation.

An example of speciation is aluminum (spelt aluminium outside the United States) present in the metal form versus aluminum present in the oxide form (Al2O3). In these cases, aluminum exists in two different oxidation states (Al0 vs. Al3+) with highly diverse properties. As an example, the former can be highly explosive when the powder form is dispersed in an oxidizing environment (this acted as a booster rocket propellant for the space shuttle when mixed with ammonium perchlorate), while the latter is extremely inert (this is the primary form aluminum exists within the earth's crust).

Aluminum foil (the common household product) is primarily metallic. This, however, is completely inert to the environment (air under standard temperature and pressure) since it is covered by a thin oxide layer that naturally reforms when compromised