A novel tool to facilitate the learning of thermodynamic principles by undergraduate students of the biological area.

This study describes the application and evaluation of a novel didactic tool (thermodynamic device) developed for students in the area of biology who have conceptual deficiencies that render the learning of thermodynamic principles difficult. Systems of communicant vessels with equal and different compartments were constructed to correlate the equilibrium constant of the reactions and reagent/product ratios with the concept of standard and nonstandard Gibbs free energy changes (ΔG° and ΔG, respectively). The communicating vessels were filled respectively with equal and different volumes of a dye aqueous solution followed by the opening of a faucet that coupled the vessels. This procedure allows liquid flux leading to the movement of internal propellers. The movement of the propellers turns on an electronic circuit that processes the information to exhibit the energy released by the movement of the solution toward equilibrium. The thermodynamic device was evaluated regarding the efficiency of content comprehension and retention of the gain by challenging students to answer five subjective questions 1 week after a regular teaching module about thermodynamics. The overall mean score obtained by the students who accessed the thermodynamic device (7.0) was significantly higher (p < 0.01) than the mean score of the control group (3.4). The thermodynamic device increased twofold the percentage of students who gave more than 50% correct answers. The efficiency of the didactic tool was also evaluated and corroborated by objective questions. In conclusion, the use of the thermodynamic device was highly effective in improving the understanding of thermodynamic principles by undergraduate biology students.

A novel tool to facilitate the learning of buffering mechanism by undergraduate students of the biological area.

In this study, the application and evaluation of a novel didactic tool (buffer kit) is described to make it easy for students in the biological area to overcome their conceptual deficiencies that render the learning of the buffering mechanism difficult. The buffer kit was constructed with double-face EVA cards with a conjugated acid formula (H2CO3 or H2O or H3 O⁺ ) printed on one face and the respective conjugated base formula (HCO -³ or OH⁻ or H2O) printed on the reverse face. The conjugated acid and base faces were exposed after adding extra H⁺ and OH⁻ cards, representing the addition of strong acids and bases, respectively. The buffer kit was evaluated with regard to the efficiency of content comprehension and retention of the gain by challenging the students to answer four subjective questions one week after a regular teaching module about the buffering mechanism. For each evaluation round, the buffering mechanism was taught to the control student group without the support of the buffer kit and, to the test student group, an identical content was taught, however, supported by the buffer kit. The overall mean scores obtained by the students who accessed the buffer kit (5.0) were significantly higher (p < 0.01) than the mean score of the control group (3.0), and the buffer kit increased twofold the percentage of students who gave more than 50% right answers. The use of the buffer kit was highly effective in improving the understanding of undergraduate students of the biological area about the buffering mechanism and the application of the Henderson-Hasselbalch equation.