Steven A. JonesAssociate Professor

Biomedical EngineeringLouisiana Tech University

Created for our NSF-funded Research Experiences for Teachers Program

The Scientific Method &Engineering Design Process

Definitions

Scientific Method (SM): A process through which observations and experimental results are used to provide a theoretical framework that is consistent with all data and that enables predictions of future outcomes.

Engineering Design Process (EDP): A process that applies scientific knowledge, prototyping and measurement to create a device that will fulfill a need.

This presentation will suggest several connections between these two processes. First, a schematic of the SM is shown in the next slide.

The Scientific Method

Experimental Setup

Observation Hypothesis

PredictionExperiment

Theory

Accumulated Evidence

Experimental Result

Observing

EDP

EDP

Ideas

Idea 1: The formal flow of the SM is:

Observing to Observation to Hypothesis to Prediction to Experimental Setup to Experiment to Experimental Result to Accumulated Evidence to Theory

However, the process is rarely linear, and in practice one may move from any block of the schematic to any other block.

Ideas

Idea 2: The SM may require the EDP as an internal component. For example, it may be necessary, as part of an experimental setup, to design a new device that performs a specific function.

Idea 3: Although data collection that is not directed toward answering a specific question is usually minimized in descriptions of the SM (and usually discounted as a “fishing expedition”), there are situations in which it is useful to obtain data simply to “see what happens.”

Ideas

Idea 4: A good experiment is designed to find the answer to a specific question. However, experiments can lead to new information that was not anticipated as part of the original experimental design. These unanticipated results can be categorized as Observations that may lead to new hypotheses and new experiments.

Definitions

Theory: A concise set of principles that explain and relate a wide variety of observations.

Hypothesis: A proposed explanation of (1) an observation, (2) a pattern or apparent contradiction in the accumulated evidence, or (3) a component of a theory that is not yet well described.

Accumulated Evidence: The combination of observations and experimental results.

Prediction: A result that would be expected logically if a given theory or a given hypothesis is correct.

Definitions

Experimental Setup: A context in which a prediction can be tested. The context is likely to include hardware to manipulate a situation and to make measurements, but may also include a setting (e.g. an archeological site, an ecological niche, a galaxy). One experimental setup may be used to test multiple predictions with multiple experiments.

Experiment: A process designed to test the validity of a prediction. The results of a well-designed experiment has value regardless of the result, i.e. whether the prediction is true or false. Experiments may lead to an answer of the question for which it was designed (experimental results) or it may lead to information that was not the direct objective of the experiment (observations).

Experimental Result: An answer provided by an experiment that was designed specifically to provide that answer.

Definitions

Observation: A phenomenon or event that is observed, but is not an anticipated result of an experimental design. Observations may result from experiments, observing, analysis of a theory, analysis of a hypothesis, or analysis of accumulated evidence,

Observing: Paying attention to a situation to gain insight, but not to answer a specific question.

Fishing Expedition: An inquiry in which multiple tests are conducted and multiple measurements are made, and where no specific prediction or hypothesis is to be tested.

Needs Analysis

Design Criteria

Design ConceptTest

Device

Accumulated Evidence

Test Result

Tinkering

Model

The Engineering Design Process

SM

SM

The Scientific Method

Experimental Setup

Observation Hypothesis

PredictionExperiment

Theory

Accumulated Evidence

Experimental Result

Observing

EDP

EDP

Ideas

Idea 1: Each block in the EDP is equivalent to the block in the same position of the SM. For example, in the SM, an Observation represents a Need. Just as the EDP is used to fulfill a given need, the SM is used to fulfill the “need” to explain a given observation. Similarly, a “Design Criterion” represents the hypothesis that, “the given Design Criterion is fulfilled by the designed device,” and each Test is an Experiment to determine whether the Design Criteria are satisfied.

Ideas

Idea 2: Just as the EDP is an internal component of the SM, the SM is an internal component of the EDP. I.e., it may be necessary to test scientific hypotheses as a way to find the most appropriate model of a given design or a given component. Thus, the EDP and the SM together are a recursive system. Scientific theories enable new engineering designs, and new engineering designs enable the formulation and testing of scientific theories.