Virtual Classroom Critical Thinking as an Alternative Teaching Model to Improve Students' Critical Thinking Skills in Pandemic Coronavirus Disease Era

Critical thinking skills are one of the thinking skills needed to live in the 21st century and the era of the Industrial Revolution 4.0. This study aims to develop a Virtual Classroom Critical Thinking (VC2T) Model, which is valid, practical, and effective to improve students' critical thinking skills. VC2T model has six steps: problem orientation, formulation, group discussion, analysis, result discussion, and reflection. This study is a Research & Development (R & D) involving 33 high school students in Surabaya, Indonesia. Before being tested, the VC2T Model was designed based on the theory of Plomp and Nieveen and then validated by 3 (three) experts in physics education. Data were analyzed using validity by experts, implementation of teaching with the VC2T Model, paired t-test, calculation of n-gain, effect size and percentage of student responses. The results showed that the VC2T Model is: (1) valid with an average validity score of 4.14 in the high validity category; (2) practical with an average score of implementations teaching of VC2T Model 4.26 in the outstanding category; and (3) effective as indicated by increasing of students' critical thinking skills scores which are statistically significant at alpha .05, the average n-gain is .38 in the medium category, the effect size of 6.93 is in a strong category and the average students' response is 87.59 % with outstanding category.