High School Ocean Lesson Plans: The Art of Scientific Thinking

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The Scientific Method

Topics Covered in this Section:

Overview

The scientific method is the cornerstone for discovering facts and creating theories about the Universe we live in. It is the orderly process by which scientists generate questions and hypotheses about nature. From these questions, scientists can design experiments or draw upon sets of observations to answer those questions and test those hypotheses. Most of what we learn in science is the result of some application of the scientific method. To better understand where that knowledge comes from (and whether we should trust it!), we examine herein.

What's A Good Question?

Your first assignment as a new oceanographer (or as any scientist, for that matter) is to learn how to pose a well-defined, well-constrained scientific question. The hardest job for any scientist is to ask a good question. A properly posed scientific question gets to the root of the matter; the mere creation of it suggests possibilities we might never have considered; the asking of it illuminates gaps in our knowledge and exposes those parts of a problem that are most critical.

This first and most crucial step in the scientific approach to understanding the world around us involves a lot of creativity. If you thought scientists weren't creative, then look around you. Most of the gadgets that make our lives easier were hatched by a scientist stuck in a dark lab somewhere. Many great scientists, Nobel prize winners, were artists, musicians, poets, or writers. Revolutionary scientific thinking requires an playful, insightful, and creative mind. Great scientists have an intuitive feel for the marvelous and mystical machinery of nature. They must!

I'll give you an example. The discovery of benzene, a common solvent, a component of gasoline, and a simple ring-shaped molecule with six sides‹came as a result of a dream. The scientist studying this compound dreamed that six monkeys were chasing each other in a circle while grasping the tail of the monkey ahead of them. Upon awakening, the scientist realized that benzene had a ring-like structure, something no one realized beforehand.

One of the greatest observational "scientists" of all time (though I doubt he would call himself a scientist), Henry David Thoreau, once wrote: "No way of thinking or, however ancient, can be trusted without proof." As if to prove his point, he spent two years and two months living at Walden Pond. His reasons for going inspire me every time I read them; they remind why I wanted to be a scientist. In Walden, he wrote: 

"I went to the woods because I wished to live deliberately, to front only the essential facts of life, and see if I could not learn what it had to teach, and not, when I came to die, discover that I had not lived. I did not wish to live what was not life, living is so dear; nor did I wish to practice resignation, unless it was quite necessary. I wanted to live deep and suck out the marrow of life, to live so sturdily and Spartan-like as to put to rout all that was not life, to cut a broad swath and shave close, to drive life into a corner, and reduce it to its lowest terms, and, if it proved to be mean, why then to get the whole and genuine meanness of it, and publish its meanness to the world; or if it were sublime, to know it by experience, and be able to give a true account of it in my next excursion."

This is the essence of scientific thought_to "front only the essential facts of life." From these thoughts, a new picture of the world emerges. A new understanding of scientific facts brings about paradigm-shifts, revolutionary changes in the way we look at nature and perceive its mechanisms, such as realizing that the Earth was not the center of the Universe, a paradigm held for centuries.

Thomas Kuhn, a modern day philosopher from the Massachusetts Institute of Technology, devoted an entire book to these "revolutions" in scientific thinking. In The Structure of Scientific Revolutions, he writes:

"If science is the constellation of facts, theories, and methods collected in current texts, then scientists are the men who, successfully or not, have striven to contribute one or another development to that particular constellation. Scientific development becomes the piecemeal process by which these items have been added, singly and in combination, to the ever growing stockpile that constitutes scientific technique and knowledge."

He goes on to write:

...Sometimes a normal problem, one that ought to be solvable by known rules and procedures, resists the reiterated onslaught of the ablest members of the group within whose competence it falls. On other occasions a piece of equipment designed and constructed for the purpose of normal research fails to perform in the anticipated manner, revealing an anomaly that cannot, despite repeated effort, be aligned with professional expectation. In these and other ways besides, normal science repeatedly goes astray. And when it does‹when, that is, the profession can no longer evade anomalies that subvert the existing tradition of scientific practice‹then begin the extraordinary investigations that lead the profession at last to a new set of commitments, a new basis for the practice of science. The extraordinary episodes in which that shift of professional commitments occur are known...as scientific revolutions. They are the tradition-shattering complements to the tradition-bound activity of normal science."

These episodes of scientific revolutions have been repeated throughout the history of science. They reveal, in fact, the "humanity" of science. Most people don't like change, or, at the least, are uncomfortable with change. As Ernst Mayr, a highly regarded zoologist from Harvard, puts it: "It should not be concealed...that the open-mindedness of scientists is not without limitations. When theories are 'strange' or alien to the current intellectual milieu, they tend to be ignored or silenced."

These kinds of statements emphasize that new and creative ideas in science are essential to scientific progress. This creative side of science is oft overlooked, but it is one of the most important traits a scientist can have.

What is a Hypothesis?

The kind of thinking on which most science is based is known as the hypothetico-deductive method. The first step in this method is to generate hypotheses based on observations and the posing of questions. Darwin called this first step "speculating." The next step is to perform experiments or make observations that permit testing of these hypotheses. The deductive method attempts to "deduce" facts by eliminating all possible outcomes that do not fit the facts. Hypotheses are formed and framed in a manner that excludes possibilities. Experiments are performed in a manner that attempts to disprove these hypotheses. In this way, all possible outcomes are excluded until only one possible outcome remains (ideally, but this almost never happens).

The opposite approach, the inductive approach, bases its thinking on a "house of cards"-type mentality. Inductive scientists reason that if such and such experiment always gets the same result, than that result must always be true. It was this kind of thinking that led early scientists to believe in spontaneous generation. Every time these scientists put some grain, bread, and water in a box in the lab, they "created" rats. This result happened without fail, until someone tested the possibility that the rats were migrating to the box from somewhere else. Honest to goodness, there was a time when people had no clue what caused reproduction in mammals (including humans). The best idea was either divine inspiration or some combination of plants and chemicals that caused animals (and babies) to appear.

Using hypothetico-deductive reasoning, scientists attempt to disprove things. There is no such thing as absolute proof. Scientists can only say with certainty what won't happen or what's most likely not going to happen. Karl Popper, another modern scientific philosopher, states that "any principle that cannot be falsified is outside the realm of science." Proving whether little green men live on another Galaxy is currently beyond the realm of science. There is no way to disprove this claim. However, proving whether little green men live on Mars may now be a valid scientific claim. Our hypothesis is best stated as "Little green men don't live on Mars." By exploring Mars, we can determine the falseness of this statement.

These differences might seem subtle, but that is the critical factor in generating good and testable scientific hypotheses. Good hypotheses lead to new hypotheses, perhaps better defined and more narrow in scope. Good hypotheses and well-crafted experiments let us home in a problem, they narrow the range of possibilities and help us eliminate extraneous ideas.

Another trait of a good hypothesis is that it generates a set of predictions from which we can formulate tests or experiments. In the case of no aliens live on Mars, we might predict that no signs of alien life will be present, i.e. no habitats, food, wastes. If we find anything that remotely resembles a sign of life, then we might begin to have evidence that this hypothesis is wrong. In the case of aliens do live on Mars, we really wouldn't know a priori what to look for. To disprove this hypothesis, we would predict that an alien house exists. What does an alien house look like? What do their food and wastes look like?

The hypothetico-deductive approach is the essence of modern scientific discovery. As Ernst Mayr describes it in his book The Growth of Biological Thought:

"The reason why the hypothetico-deductive method has been so widely adopted is that it has two great advantages. First, it fits right in with the growing conviction that there is no absolute truth and that our conclusions and theories should continually be tested. And second...it encourages the continuous establishment of new theories and the search for new observations and new experiments that either confirm or refute the new hypotheses."

As for the importance of good scientific questions, Mayr summarizes Collingwood who stated that "a hypothesis is always a tentative answer to a question...the posing of a question is really the first step on the path toward a theory...The history of science knows scores of instances where an investigator was in the possession of all the important facts for a theory but simply failed to ask the right question."

Good questions come from good observations. By looking carefully and insightfully at the world around you, by allowing yourself to be puzzled by phenomena that you think you understand, by "unknowing" what you know, you will be taking that first small step towards finding a sound scientific question that leads to a profound scientific theory.

What is Scientific Thinking?

Let's define a few of these terms as scientists use them:

Hypothesis: an educated guess as to the outcome of a particular experiment or phenomenon.

Observation: a set of data based on measurements obtained using one or more of the five human senses, including instrumentation designed to enhance those senses, such as telescopes or microscopes.

Data: a set of observations

Experiment: a test designed to eliminate a possible outcome or to verify the occurrence of a phenomenon

Theory: a hypothesis that has withstood the test of time

Prediction: statement of a particular outcome that must be true if a hypothesis is true.

How do scientists apply these terms? Try it. Look around you. Make careful observations. What do you see? What kind of phenomena define the ocean? the beach? the coast? What kind of organisms travel along or within the beach or sea? What kinds of things can't you see that you might be curious about? Don't limit yourself or your thinking. Stretch your mind. Include, the sea, the sky, the land. Observe the big picture as well as the tiny picture.

Write your observations in the form of questions. Ask yourself if the question would be easy to answer through experiment or further observation. If not, try to think of a way to ask the question that might make it easier to answer.

Once you have finished writing your questions, pick one and try to form a couple possible answers. Frame them in the form of hypotheses. Try to decide whether your hypothesis is better framed as a negative or positive.

For any hypotheses, list some predictions that might be true if the hypothesis is true. What do you expect to see based on your hypotheses?

If you're starting to look at the world a bit differently now, you've suceeded. You've taken your first step into the art of scientific thinking.


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