How Do You Know? Writing about Critical Thinking in Introductory Level Science Courses

by The Coalition of Women Scientists: Guiseppina Kysar, Rebecca Ericson, Cynthya Beck, & Hillary Cressey

Last summer the Coalition of Women Scientists (C.o.W.S.), a team of faculty dedicated to teaching introductory science classes, was sponsored by the Critical Thinking Across the Curriculum initiative to develop a set of modules for improving critical thinking skills across the gen ed STEM disciplines— Science, Technology, Engineering and Mathematics. Our approach focuses on scientific inquiry to help students gain the ability to apply their knowledge to new and more complex problems, whether or not science will be their career. In the short written papers that follow each module, we want students to analyze the problem proposed by an assignment, explain the steps they undertook to carry out the assignment, synthesize and evaluate their results, and, finally, consider the limitations as well as other possible outcomes.

The modules we developed are targeted interventions that instructors perform with the class based on the results of a pre-assessment exercise. In order of increasing complexity, these modules deal with the language of science (units, scales, rates and data representation), the scientific method, and how science comes to society through the media. The effectiveness of the modules and the level of students’ mastery of critical thinking skills should be visible in the short papers they write. Our approach challenges the use of pre-formatted assignments that prevent students from writing complete thoughts and/or limits their input to simply restating a problem or an expected outcome/solution.

The science of M&M’s is our most successful example of the second “How Do You Know?” module, which addresses science as a way of knowing. Traditionally this topic is dealt with in lecture where it is taught as a set of steps common to all scientific disciplines. Students are required to be familiar with the scientific method, but not to know how to apply it. Instead our module gives the students an opportunity to assess assumptions, draw conclusions (make judgments) and consider alternative perspectives or solutions. The module consists of a simple experiment designed to test a hypothesis generated by the students. For this exercise the students are given a clear plastic cup half filled with a mixture of regular M&M’s and a few peanut M&M’s. They are asked to shake the cup and to observe any change in the spatial distribution of the candies. They are prompted by questions to identify variables, frame observations, and analyze the data. Later they are asked to formulate a scientific hypothesis and a test to validate their hypothesis, including possible alternative solutions. The questions require a written short answer (limited to one paragraph per question).

The “How do you know?” module, like the other modules, has a three-step design—a pre-test worksheet to measure level of effort and knowledge, an intervention by the instructor who clarifies, emphasizes and fine tunes the crucial aspects of the module, and a re-take of the module’s exercise. In the second, most crucial phase, the instructor must be very intentional in modeling the thinking process and illustrating with examples how the four indicators of critical thinking should be addressed in the writing. If needed, students can carry out more observations and are allowed to re-write as much of their work as they deem necessary. Both pre- and post assessments are graded on the same rubric (see below), which is modeled on Bloom’s taxonomy of the cognitive domain.

The “How do you know?” exercise is not about discipline-specific content, although an application of this problem—the spatial distribution of objects of diverse sizes—is tackled in several scientific disciplines. Rather, it’s about thinking as a scientist. The main leap for students is to understand that science is knowledge in progress that can be accessed in an active way rather than as accumulated memory archives. The “how do you know?” approach emphasizes the thinking process to achieve the answer. For this approach, students must make their writing reflect their thinking.

We are convinced that clear writing identifies clear thinking; therefore, in these short written pieces we are looking for these indicators of critical thinking in scientific writing (a sentence is enough to qualify for scientific writing):

1. Proper use of English grammar and syntax to prove that clear communication is essential in the sciences;
2. Proper use of scientific notation and vocabulary as evidence of mastery of the scientific language;
3. Recognizable standards of comparison (e.g. smaller than…) and strength of arguments (if… then) as evidence of following basic logical steps;
4. Conciseness that reflects the ability to summarize effectively the points sought after in the question.

We are encouraged so far by the positive results of the pilot modules in several sections of general education Biology and Astronomy. We’ve noticed that participating students show a significant increase in the level of engagement with their own learning. We attribute these improvements to the reflection on their work that students need to carry out to write meaningful answers and to the sense of accomplishment that students feel by becoming aware of their own problem-solving abilities. As for the M&M’s exercise, it is possible that the students’ positive response may be enhanced by the fact that they can eat their experiment at the end of the class.