The scientific method is part of a rigorous critical thinking process by which new ideas about how some part of the natural world works are put to the test.

Observation and Description:

·        The stimulus for almost all environmental research, whether in the field or lab, comes initially from the observation of a distinctive pattern in nature.

·        An idealized study consists of two general stages:

1) Descriptive stage; concerned with whether or not a distinctive structural patterns exists.

·        Structure refers to measurable conditions of the system at one point in time 

(e.g. physical conditions in temperature).

2) Functional stage; in which the cause or effect of this pattern is explored.

·        Function refers to processes that create the structure at a given instant, and how these processes are affected as the structure changes (e.g. rates of nutrient cycling, pollution).  

Descriptive Stage

Formulate Descriptive Hypothesis:

·        Alternative Hypothesis: In effect, predicts that a difference in structure exists.

·        Null Hypothesis: States that no difference exits, such that the difference between two or more sets of data is not greater than expected by chance.  Or, the values obtained in an experiment or set of observations do not differ from a theoretical expectation.

·        A formal test of a hypothesis is carried out by stating the null hypothesis (H_o), collecting unbiased observations or experimental data, and performing a statistical test of the null hypothesis.

·        Rejection of the null hypothesis results in acceptance of the alternative hypothesis.

Data Collection and Statistical Test of Hypothesis:

·        A hypothesis is tested by collecting and analyzing data to determine if the difference exists with a probability greater than that expected by chance. Such a test usually requires the collection of unbiased, quantitative data that can be analyzed statistically.

·        These steps form the descriptive phase of the study, and they determine, with a specified degree of probability/uncertainty, whether or not a structural patterns exists.

·        If a structural difference exists, the stage is set for studies of function.

Functional Stage

Postulate Cause or Significance of Demonstrate Difference:

·        To examine causes or consequences, one must first identify the possible cause-effect relationships that might be operating.

Formulate Functional Hypothesis:

·        Hypothesis about functional relationships of the observed pattern.

Conduct Controlled Experiments or Observations:

·        Controlled experiments or controlled observations can be designed to distinguish among possible cause-effect relationships.

Interpret Relationships and make New Predictions:

·        Provide inferences about the data, apply knowledge to solve a problem.

·        Description and decision phase of critical thinking model; only the final stage of a particular cycle.

·        All decisions are open to re-examination and modifications, as new content/data becomes available.

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