Jeffrey S. Coker
Elon University
Biology

Scientific Method Applied by Non-majors in Introductory Biology Class

Background

Modern science is generally done by small groups of people asking questions, designing and carrying out experiments, analyzing data, and presenting results.  Inevitably, the results lead to more questions, which then serve as the basis for another set of experiments.  It seems logical that students would be introduced to modern science through a similar process.  Nevertheless, students in introductory science classes are rarely asked to complete a complete cycle of the scientific process. 

There are a multitude of different approaches for teaching introductory labs, but the most typical in American universities involves 10 to 15 separate lab sessions where students perform small parts of the larger scientific process.  In a typical session, students carry out a set of instructions which leads them to some pre-determined finding.  Typically, the pre-determined findings are supposed to illustrate a concept or set of concepts which students are supposed to learn.  This is the essence of so-called “cookbook labs.”

Over the last two decades, science education has slowly begun shifting in the direction of more inquiry-based approaches, emphasizing the processes of science and critical thinking over “cookbook labs” and memorizing content.  Some courses have adopted guided inquiry approaches where students are given questions, hypotheses, and/or other guidance, but are allowed some flexibility within the experimental framework so that results are not pre-determined. 

A few introductory courses have gone even further, adopting open inquiry pedagogies in which students can design, implement, analyze, and present their own experiments.  The ultimate form of inquiry, independent research, involves an original open inquiry which builds upon existing literature to discover new knowledge. 

This study evaluated an open inquiry pedagogy for introductory biology labs where students designed, implemented, analyzed, and presented their own experiments.  The labs took place in “Reinventing Life,” a course for non-science majors which investigates how the biology of life is changing in the 21st century.

Pedagogy

The lab in this study involves one week of introduction on scientific experimentation followed by four 3-week lab modules, each corresponding with one of the four major sections of the course.  During the first week of class and/or lab, students participate in a discussion on characteristics of good experiments and read a 20-page guide to scientific experimentation.  The discussion and written guide explain the process of scientific investigations including coming up with a topic, asking a scientific question, developing a hypothesis, designing an experiment, observing and recording data, analyzing data, making conclusions, and presenting results.

For the rest of the semester, students complete four 3-week lab modules.  In each module, students work in small groups to design, implement, analyze, and present their own experiments.  In the first week of each module, students are given a handout with general instructions, hints related to the sampling tools available, and a reminder of what constitutes a good experiment.  Students are also given tools which are appropriate for a given topic.

For example, for the “Ecological Change” module, student groups are given a bucket with measuring tape, rope, scales, hand shovels, collecting bags, stakes, orange flags, protractors, etc.  The goal for the first week is for each group to ask a question, make a hypothesis, design a proper experiment, and get the instructor’s approval.  For homework, student groups find background information on their topic and make any other preparations for their experiments. 

In the second week of each module, students collect data for their various experiments and begin analysis.  Computers are available to students so that they can immediately begin using spreadsheets, making graphs, drafting lab reports, etc. 

The goal for the second week is for students to complete data collection and begin analysis.  For homework, students must complete a full lab report (in the traditional format with an Abstract, Introduction, etc.).  They are encouraged to work on analysis and graphing in groups, but each student is required to turn in their own lab report in their own words.

During the third week of each module, students turn in written lab reports (individually) and make short, informal presentations to the class (in groups).  Students are given 15 minutes to talk within their group before presentations begin.  After each presentation, other students in the class are encouraged to ask questions.  The instructor and TAs use this time to emphasize experimental methods, different strategies for finding answers to questions, and any notable results.  Instructors wrap up the session by inviting self-reflections on what groups are doing well and how they could improve their experimental approaches.

Research Methods

Student-designed experimentation was studied using several different techniques, including pre- and post-surveys of entire classes, videotaping of individual student groups as they worked through the multi-week labs, videotaped exit interviews, and the evaluation of lab reports from experiment to experiment.

Novelty of Student-designed Experiments

On course pre-surveys, the vast majority of students indicated that they had previously done every part of the typical scientific process.  However, these experiences had been very fragmentary for them.  For example, they may be asked to develop a scientific question and hypothesis in one activity, and then in another activity might be given an experimental protocol and asked to gather data and analyze results.  They rarely completed the whole scientific process as one integrated activity.

The reality of students’ prior experiences seemed to be captured by the following question:  “Before this class, have you completed your own experiment from beginning to end, including asking your own question, designing an experiment, carrying it out, analyzing data, and presenting results/conclusions?”  Only 20% of students answered yes.  Since Elon University students represent an above average selection of American high school graduates from across the country, this does not speak well about science experiences on a national level.  Conversations with colleagues at other institutions suggest the same conclusion – students are not being asked to complete scientific investigations from beginning to end.  In the Reinventing Life course, this meant that 80% of students were completing their own experiments for the first time.

Student Learning and Performance

In terms of learning outcomes, the open inquiry pedagogy used in this study resembles undergraduate research (albeit on a small scale) more than it does the traditional introductory lab course.  Specifically, students made significant improvements in terms of understanding scientific process, experimental skills, and critical thinking.

Student performance improved significantly with each experiment, especially from the first to the second.  This trend included mastery of scientific process as seen in videotapes of lab sessions, lab reports, and interviews.  Furthermore, some students were able to do truly outstanding experiments.  This is very different from labs with pre-determined results, where the best a student can do is find “the” correct answer.  When students design their own experiments, there is no glass ceiling.

A common concern about using open inquiry is that students might learn less “content.”  In this study, student surveys, lab reports, and exit interviews did not suggest that they learned any less content.  However, it was true that every student group learned a different set of content which depended on their experimental topics.  As a result, content learning became more difficult to evaluate.  Student content learning in open inquiry situations must be judged primarily from writing and speaking, and not from a common set of test questions.

Student Perceptions

Student perceptions of their learning experiences were very positive.  A sample of student comments from evaluations is shown below:

“I learned a lot.  Giving us freedom and responsibility to design our experiments made a huge difference.”

“Working with a group allowed me to come up with interesting experiments, and I found that the experiments and reports got better over time.”

“At the beginning of the semester, I was not confident in my lab skills.  I am proud to have performed my own experiments and found success.”

“At the beginning of the semester, it was difficult to figure out what to do.  But by Lab 2, we did incredibly well at designing an experiment.”

Comments emphasizing improvement were very common.  In interviews and on post-surveys, students were often adamant in saying that they felt much better about doing science at the end of the semester.  Likewise, on post-surveys students were asked “After this lab, do you feel more comfortable doing science?” and “After this lab, do you have a better understanding of how science works?”  To both questions, 100% of students answered “Yes.”

1. Provide criteria for “good” experiments.

A fear about using open inquiry is that students might do low quality experiments that will not seem worth the time.  A key to stimulating higher quality was to be very clear about criteria for “good” scientific experiments.  Emphasizing specific, focused questions was especially effective, since the initial question tends to set the tone for the entire experiment.  The following guidelines were also emphasized repeatedly:

     1.  Ask a very specific, testable question.
     2.  Test a control for comparison (a group that does not receive the experimental treatment).
     3.  Use a sample size large enough to allow firm conclusions.
     4.  To understand a whole population, obtain a random sample of that population to avoid bias.
     5.  Replicate each part of the experiment (at least 3 times).
     6.  Hold all variables constant between trials except the variable being tested.
     7.  Collect quantitative data whenever possible.
     8.  Measure using metric units.
     9.  Gather data carefully and accurately.
     10.  Be objective and honest.

Some of these guidelines are generalizations that might not be true for every type of experiment, and students were made aware of this fact through examples.  Nevertheless, the ten guidelines provided a very useful set of criteria which encouraged students to perform quality experiments. 

2. Emphasize honest analysis.

Because of students’ prior experiences where they are graded on their ability to find and explain pre-determined results, students were nervous at first about open inquiry. 

Most needed to be explicitly told that they were free to do “real” science - supporting a hypothesis is fine, disproving a hypothesis is fine, and inconclusive experiments are also fine. 

When students believed that they would be graded on scientific process, they then felt the freedom to do real science, be more creative, and embrace open inquiry.

3.  Do at least two student-designed experiments.

In most high school and college classes, student-designed experiments (when they occur) are nearly always a singular experience.  For example, high school students might complete a science fair project while college students might complete their own investigation at the end of a course.  Nevertheless, patterns of student learning across four student-designed experiments suggest that the biggest jump in student learning takes place during the second experiment. 

During the first experiment, students struggle to understand the overall process and the expectations for a “scientific” investigation.  Then, after completing lab reports and presentations and getting feedback on them, the experience “clicks” with many students.  Enjoyment and performance increase significantly during the second set of experiments.  The third and fourth experiments also lead to improvements, but they are minor compared to what happens in the second experiment.  For teachers, these data suggest that students should be asked to complete at least two experiments.  Since this study involved non-science majors, it would be interesting future studies to examine this possibility in introductory and upper-level courses for science majors.