David Bloomberg
Theories.

From _College Chemistry_, 8th Edition, by Henry F. Holtzclaw, Jr. 
and William R. Robinson (U of Nebraska and Purdue U, respectively), 
D.C. Heath and Company, p. 10 (anything in all caps was boldfaced or 
italicized in original):

"The Scientific Method

Your study of chemistry will be concerned with the observations, 
theories, and laws that give this science its foundation and that 
form a framework into which information fits to make an integrated 
area of knowledge. This framework develops from the pursuit of 
answers to many questions, each of which can be subjected to 
experimental investigation by an approach often called the 
SCIENTIFIC METHOD.

Scientists identify problems or questions through their own 
observations and experiments or from the observations, experiments, 
and conclusions of others. (Problems are often identified when 
experiments do not go as expected.) The first step in applying the 
scientific method to a problem involves carefully planning 
experiments to gather facts and obtain information about all phases 
of the problem. The results are examined for general relationships 
that will unify the observations. Sometimes a wide variety of 
observations can be summarized in a general verbal statement or 
mathematical equation know as a LAW. One example is the law of 
conservation of matter (Section 1.3), which summarizes the results 
of thousands of experimental observations. More often, however, a 
tentative explanation is suggested. Such a proposal is called a 
HYPOTHESIS. For instance, Dalton attempted to explain why mass is 
conserved in a chemical reaction when he first presented his ideas, 
which were really hypotheses, of the atomic number of matter. A 
hypothesis is tested by further experiments, and, if it is capable 
of explaining the large body of experimental data, it is dignified 
by the name THEORY. Dalton's ideas have been so extensively tested 
that we now refer to the atomic theory. Theories themselves can 
prompt new questions or suggest new directions in which additional 
information can be sought."

From _Outlines of Physical Chemistry_, by Farrington Daniels (U of 
Wisconsin), John Wiley & Sons, Inc. P. 4:

"SCIENTIFIC METHOD. Chemistry and all other sciences are based on 
experimentally established facts. When a number of facts have been 
collected and classified, we may draw inferences as to the probably 
behavior of systems under conditions which have not been 
investigated. When a number of phenomena have been observed and 
studiedd with exact measurements, we can often develop a LAW which 
will predict the behavior of similar systems under different 
conditions. The law is not necessarily an expression of infallible 
truth but is rather a condensed statement of facts which have been 
discovered by experiment. It enables us to obtain facts which are 
needed without continued recourse to experiment.

Natural laws may be discovered either by the correlation of 
experimentally determined facts, as we have just shown, or by means 
of a speculation as to the probable cause of the phenomenon in 
question. Such a speculation regarding the cause of a phenomenon is 
called an HYPOTHESIS. After an hypothesis has been subjected to the 
test of experiment and has been shown to apply to a large number of 
phenomena it is termed a THEORY."

The Third College Edition of Webster's New World Dictionary of 
American English, gave the following under SYN for theory:

"SYN.--THEORY, as compared here, implies considerable evidence in 
support of a formulated general principle explaining the operation 
of certain phenomena (the THEORY of evolution); HYPOTHESIS implies 
an inadequacy of evidence in support of an explanation that is 
tentatively inferred, often as a basis for further experimentation 
(the nebular HYPOTHESIS); LAW implies an exact formulation of the 
principle operating in a sequence of events in nature, observed to 
occur with unvarying uniformity under the same conditions (the LAW 
of conservation of energy)"

The following has been added as an update, to further bolster the 
above:

"`Theory' -- to a scientist -- is a concept firmly grounded in and 
based on facts, contrary to the popular conception that it is a hazy 
notion or undocumented hypothesis." -- New Orleans Geological 
Society, 1985