“Turn on the Coconut!”
Advanced technology befuddles primitive people when they first stumble on it. With a real-world experience that barely extended to the perimeters of their island, South Pacific natives viewed technology during World War II as magical in both existence and creation. To retrieve all the good things they experienced when troops first arrived to fight the enemy, local tribes fell back on the only means at their disposal — replicate the conditions under which the goodies first arrived. Coconut shells passing for radar antennae quickly appeared, along with fake airstrips and bamboo watchtowers; the goodies, however, never materialized.
In Surely You’re Joking, Mr. Feynman!, physicist Richard Feynman used cargo cults to critique activities that look scientific at first glance, but fail to reflect the rigor and conceptual meaning of scientific investigation. Cargo cults in essence teach us that merely emulating the behaviors of scientists in science is insufficient. Like real scientists, students may formulate hypotheses, design experiments, record data, and even prepare speeches to present results. These activities all look scientific. But are they truly scientific?
“I Used Cherries for the Chromosomes”
Most parents, typically the only help available to students at home, lack sufficient content knowledge to help their children on scientific content. In response, teachers lower the rigor of take-home projects to the rote completion of steps. Let us examine the timeless biology activity in which students go home and bake cakes to represent cells, decorating them with various fruit and candies bearing the likenesses of various organelles. What exactly do the students learn?
The upper levels of Bloom’s Taxonomy are highly cerebral; choosing whether to use cherries or walnuts to represent chromosomes is not. In fact, the bake-a-cake activity employs such little cognitive skill that aligning it to even the lowest taxonomy level (remember) gives it more credit than it deserves.
Norman Webb published a model of rigor in the 1990s that in many ways better categorizes the type of activities assigned by teachers. Judging by the Webb model, baking and decorating a cake lies at the lowest level of depth of knowledge, recall and reproduction. (See “Depth of Knowledge in the 21st Century” in the Winter 2010 issue of SEEN Magazine.)
If baking a cake to represent a cell offers no practice in higher-order thinking or doing, perhaps students learn biological concepts that they can take with them to the next level. But unless students can explain in their own words how the cherries affect the walnuts, they haven’t learned cell structure. What happens to the cake if a walnut falls off? With inadequate concept development of cell structure, students cannot say. Baking a cake won’t teach them, either. Such low-level activities therefore soak up students’ time and offer students and parents little in return other than aggravation and unnecessary expense.
“I Think the Coin Will Hold Five Million Drops”
The water-drop experiment is performed by elementary and middle school students all over the country. Oddly enough, we should not perform this experiment to satisfy the question, “How many drops of water can we place on a coin?” Who cares?
An experiment whose sole purpose is to find the number of drops we can place on a coin is worthless. In a real science classroom, we try not to simply teach students to collect data; rather, we try to instill in students the thinking processes involved in experimental design such as the proper formulation of a hypothesis. What we are seeking is the answer to the bigger question: What accounts for the number of water drops that can stay on a coin? Is it the perimeter or the surface area?
Suppose we earlier performed a water-drop experiment on a dime and found it held on average seven drops. Using this prior knowledge, formulating a hypothesis on the number of water drops a quarter can hold is a higher-order thinking activity. Is surface area or perimeter the most important factor and why? Once we answer this question, the impact can grow and possibly explain other phenomenon seen in nature. How much condensation can accumulate on a section of the Space Shuttle when flying through icy clouds? A properly designed coin-drop experiment can allow us to extrapolate the results (within reason) to answer this question.
Contrast the proper formulation of a hypothesis with the utterly worthless, “Do plants grow better listening to rock?” experiment that appears in numerous science fairs throughout the country. Like baking a cake to represent a cell, guessing wildly is barely cognitive. However, formulating a theory and relying on prior knowledge (“I know that a dime will hold seven drops”) to predict a result arising from a new situation (“How many drops will a quarter hold?”) lies at higher levels of both Bloom’s Taxonomy and Webb’s depth of knowledge.
Even very young children can benefit from a properly designed water-drop activity. Although young children may not understand the concept “double,” they understand “bigger.” Although we may find it obvious, the theory that larger coins can hold more water drops is a testable theory for this experiment at lower grade levels. Once students have seen the number of water drops a dime can hold, they can use the proposed theory to predict a larger number of drops on the quarter, removing their reliance on guessing wildly.
The MythBuster Era
One of the most popular cable television shows is MythBusters, a regular feature of the Discovery Channel. In the show, a team of talented, yet irreverent, personalities attempt to verify or refute historical myths. MythBusters is a welcome addition to television programming, for it allows children to see the inner workings of experimental design, often for the first time. Many scientific issues such as error, replicability, and old-fashioned horse sense, appear throughout the episodes.
The show, however, often lacks one key ingredient of science: higher-order thinking. In one of my forthcoming series of plays titled, Thinking Things Through, a group of teenagers watch the MythBusters episode centered on a historical myth of Romanian archery — the penetration power of an arrow doubles when fired by an archer riding on horseback. Using their understanding of work and energy and logical banter, the team members in the play agree that under ideal conditions the myth is possible; including the considerable effect of air friction renders the myth dubious.
Rather than rely on a theoretical investigation to formulate a testable hypothesis, the MythBusters crew use gut feel. This “let’s see if it works” method teaches the television audience an unfortunate misconception: Science is the testing of wild guesses.
Watching a group of physicists solve equations on a blackboard would not hold the audience’s attention for long. But teachers need to be careful in emulating the MythBusters approach to science too closely. Science is ultimately about processes, both cognitive and conceptual. Although busting a myth may teach students rote experimental procedures, it may fail to teach them how to go about understanding the world around them.
Discussion
As we have discussed, many of the activities deployed in classrooms across the country lack the cerebral component necessary to prepare students for future success. While the average person may look at a bucket of pond water and think “scum,” the microbiologist can form a deeper understanding of pond water using the lenses of a microscope. Teachers have at their disposal a lens of their own — the combination of Bloom’s Taxonomy and depth of knowledge defined as cognitive rigor — to evaluate whether the activities they assign will likely drive their students toward success in the 21st-century.