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An Introduction to the Scientific Method

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The “scientific method” is understood to be a controlled, methodical, investigative process used to analyze a specific occurrence or phenomena.  The scientific method does not necessarily relate only to the classical sciences such as physics or chemistry. It can be applied to everything from diagnosing an automotive problem, medical problem or criminal investigation. Any issue where an occurrence is observed whose cause is unknown.

The scientific method is frequently defined as the following steps:

Observation of phenomena.

Establish questions why the phenomena occurred.

Create a hypothesis explaining the phenomena.

Test the hypothesis.

Generate the answers to the questions.

The method begins with the observed phenomena. Some scientific texts will immediately jump to generating a hypothesis, but this doesn’t necessarily have to be the first step. Simply observing phenomena may not provide sufficient information to generate a hypothesis. The following example will assist the reader in understanding the scientific method and how it has been applied.

A seventeen year old budding scientist has been given a well-used Roadmonster car by his parents. Being necessarily frugal with a limited income from his part time job, he pays careful attention to his car’s fuel economy.  He notes a strange phenomenon in his travels. The Roadmonster gets 14 mpg going to and from school but 18 mpg on a trip to the beach. The first step in the scientific method, observation of a phenomenon, has occurred.

Why, he asks himself, does the Roadmonster get better mileage when traveling fast on a highway, obviously using more power? Step two has been reached as he has established a question of why the observed phenomenon occurred.

This is where some traditional views of the scientific method “jumps the track.” This budding scientist doesn’t have enough information yet to form a hypothesis to test.  He needs more information.

He decides to measure the fuel consumption of his Roadmonster at various steady speeds. He is about to establish the “baseline.”  In order to pose workable questions to be researched the researcher has to establish a baseline. That is a repeatable circumstance to which the testing can always return and generate the same result. This baseline repeatability confirms that nothing has entered the testing parameters to alter the data.

Being mechanically inclined the budding scientist installs a fuel flow meter, available from many auto parts outlets.  He can now determine his fuel flow in miles per gallon at various speeds.

His hypothesis is forming; he has already assumed that mpg should decrease with speed, not increase. He is going to prove or disprove that hypothesis.

He takes his Roadmonster out on a clear section of interstate highway and records the mpg readout from his fuel flow meter at 40, 50, 60 and 70 MPH. He returns home to analyze his data. He ensured that he also recorded the air temperature, tested on a level section of highway and recorded the data in both directions to average out any effect of wind speed and direction.

Remembering his trigonometry, he plots the data and observes he has a straight line. At 40 MPH he averages 21.5 mpg and at 70 MPH he averages 18 mpg. The mpg readings at 50 and 60 MPH fall on the straight line! His hypothesis that fuel mileage should decrease with increased speed is confirmed. The data he has gathered has been developed through an empirical method of research.

The data he has is empirical data and, if it is repeatable, it can be determined to be dependable. He can also calculate the equation for the performance curve he has generated and by plugging in a new speed he can estimate the mph at that speed if conditions are the same.

Engrossed in this research he calculates the equation to be MPG = (-.1167 X MPH) + 26.169 and excitedly estimates the MPG at 30 MPH to be 22.7 and at 80 MPH to be 16.8.  He rushes out to confirm the calculation but returns disappointed.  The numbers are not working! He can repeat the data between 40 and 70 MPH, but outside of that range something goes awry.

At this point the seasoned scientist, his father, steps in.  A “peer review” is about to take place. A peer review is an analysis of the test methods and results performed by a researcher’s peers to determine if the data and conclusions meet rigorous scientific inspection. The seasoned scientist, proud of his son’s scientific method, adds some empirical information of his own.

The typical internal combustion engine is most efficient in the neighborhood of its torque peak, that is, the RPM range where the engine develops maximum torque. At RPM ranges below or above the torque peak the engine becomes less efficient. The reason the Roadmonster did not yield better mileage at low speed is because it was out of its efficient range. Above 70 MPH, the Roadmonster’s prodigious frontal area and bulk was generating significant aerodynamic drag. A discussion of drag coefficient ensues but that can be left for another day.

So, our budding scientist has faithfully followed the scientific method and has a better understanding of it, and how an automobile functions in the real world.  His fuel flow meter will later show him how idling at a stop light, and how stop and go traffic, harms mileage.

When his observation of his fuel mileage didn’t fit his pre-conceived idea, he went about formulating a test procedure, analyzed the data and answered his question. This time honored method has been depended upon for centuries and continues to stand scientists and engineers of the world in good stead.

More about this author: James Villano

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