Why the Scientific Method is Like a Chocolate Chip Cookie Recipe

“What IS the scientific method?” asks my middle schooler. Little does she realize that the answer to this simple question hides in a historical can of epistemological worms.

Webster’s defines the scientific method as the “principles and procedures for the systematic pursuit of knowledge involving the recognition and formulation of a problem, the collection of data through observation and experiment, and the formulation and testing of hypotheses.” It’s a nice definition, but largely useless for the purposes of explaining the scientific method to a seventh grader.

In point of fact, there is no single scientific method. Like the multitude of recipes for the world’s best chocolate chip cookie, there are millions of “scientific method” recipes out there. Any set of principles and procedures may stack up as a valid or invalid “scientific method” in the eyes of a particular beholder.

In a general kind of way, the steps of the scientific method go something kind of like this:

1. Define a question.
2. Gather information and resources (observe).
3. Form an explanatory hypothesis (conjecture).
4. Test the hypothesis by performing an experiment and collecting data in a reproducible manner.
5. Analyze the data.
6. Interpret the data and draw conclusions that serve as a starting point for new hypothesis.
7. Publish results.
8. Retest (frequently done by other scientists).

Depending on the nature of the investigation, you may want to refine your experimental method when you have completed step 6, and go back to step 3. You may choose to iteratively reapply these steps until you feel you have sufficiently refined the experimental set-up so you can explain what’s going on in publishable form.

So in the case of last week’s translational and rotational motion problem involving the racing bicycle and bicycler, these steps would look like:

1. How is rotational motion related to translational motion?
2. The bicycler applies a force to the pedals which becomes a force powering the back tire.
3. The force applied at the pedal is related to the force applied at the tire.
4. The bicycler completed the 1000-meter race in 56.3 seconds.
5. An analysis of the data reveals that the force exerted at the pedal for rotational motion is over twice the force exerted by the bicycle/bicycler system via translational motion.
6. Explain this difference by looking at torque. We can confirm this by modifying our experiment (perhaps by measuring force or torque directly) and going back to step 3.
7. Write up findings in publishable form.
8. Make the data available to other researchers, who may want to run their own experiments.

There are some additional important ideas embedded in the scientific method, which can all be related to the publication aspect of the scientific method. The first is reproducibility. Anyone should be able to reproduce the outcome of your experiment. If it’s not repeatable, then the research is considered suspect. The second is external review. By publishing your work, you document and open up your scientific methodology for peer review. If they find something that suggests an improper application of the scientific method (whatever that is!), your findings are again suspect.

There are common mistakes peers look for in scientific studies. One is whether you conducted the experiment under controlled conditions. Suppose you conducted the first bicycle trial in the rain, and the second on a sunny day. These were not controlled conditions, because external factors (the weather) could have affected the outcomes of the two trials. A second is bias, both unintentional and intentional. Your personal beliefs can allow bias to creep into an experiment. Unconscious bias can sneak in if the scientist is careless, for example, in sampling data. Intentional bias can purposely be incorporated to confirm a desired outcome. Bias is closely associated with the statistical rigor of the science. When referees detect that a lack of controlled conditions and/or bias has led the scientist to a false confirmation of hypothesis, the published findings are once again deemed suspect.

So in broad strokes, this is the scientific method. But don’t expect any scientist to agree with it. Each one has her own special sauce that renders her scientific method incontrovertible, while the methods of others remain suspect.