Diffusion has often been taught in science courses as one of the primary ways by which molecules travel, particularly within organisms. For years, classroom teachers have used the same common demonstrations to illustrate this concept (e.g., placing drops of food coloring in a beaker of water). Most of the time, the main contributor to the motion in these demonstrations is not actually diffusion, but rather convection. Yet teachers, textbooks, and workbooks continue to cite these as examples of diffusion, despite having been adequately refuted. In order to reaffirm the refutations and promote greater awareness of the continued existence of these misconceptions among teachers, the authors designed an experiment to test the premise that typical classroom diffusion experiments are, in fact, examples of convection. Taking advantage of the free-fall environment through NASA' Teaching from Space Microgravity Experience, we were able to show that the great majority of dispersion patterns depicted in these demonstrations are due to convection. Subsequently, we propose classroom activities that serve as more accurate demonstrations of diffusion.

Science is a complex process, and we must not teach our students overly simplified versions of “the” scientific method. We propose that students can uncover the complex realities of scientific thinking by exploring the similarities and differences between solving the familiar crossword puzzles and scientific “puzzles.” Similarly to solving a crossword puzzle, solving puzzles in science is a complex and creative process in which hypotheses and theories evolve through the accumulation of many pieces of independent, yet interlocking, lines of evidence. We discuss the important lessons from Haack's crosswordpuzzle analogy and how it applies to teaching science.

In daily life, students are allowed to use words such as “more,” “some,” or “increase—decrease” to describe the relationship between two events. In science, concise description is necessary, which requires the contribution of math. In the summer component of the Science Research Institute program, students integrated essential math concepts with their research questions. Students designed experiments using data-acquisition units to monitor heart rate and pulse in order to obtain enough statistical power to mathematically use the words “more” or “increase—decrease.” Overall, students gained an appreciation for the requirement of math to support the scientific question and research design.

Many biology educators at the undergraduate level are revamping their laboratory curricula to incorporate inquiry-based research experiences so that students can directly participate in the process of science and improve their scientific reasoning skills. Slugs are an ideal organism for use in such a studentdirected, hypothesis-driven experience. Slugs are inexpensive, easily collected, and low maintenance. Most students are unfamiliar with slugs, and their curiosity is piqued as they observe and classify these fascinating creatures. The procedures described here offer step-by-step instructions on how slugs are used to guide students through an inquiry-based research project for 7 weeks in a majors general biology course.

Obesity is the costliest preventable health problem in the United States. Understanding and applying the first law of thermodynamics will help students prevent and treat this ail-too-common problem.

in many labs on photosynthesis, the presence of starch in leaves is used as an indirect indicator of photosynthetic activity. Students do starch tests on leaves from plants that have been kept under a variety of conditions in order to check parameters for photosynthesis. The starch test can also be used to enable students to discover differences between plants that use C₃ or C₄ photosynthesis.