This study aims to produce a chemical module based on discovery learning redox reactions using probing prompting techniques and determine the level of validity, practicality and effectiveness of the module. This research includes education development research (EDR) using the Plomp development model which has three stages, namely the preliminary research phase, the prototyping phase and the assessment phase. At the prototyping stage, self evaluation is carried out, expert review, one-to-one evaluation, small group evaluation, while the assessment stage is carried out through field tests. in two schools namely SMAN 15 Padang and SMAN 9 Padang. The research instrument used was a questionnaire in the form of validity and practicality sheets, multiple choice questions and critical thinking questions. Results Module validity by an average validator is 0.87 with a very high validity category. The results of practicality by students in small groups an average of 0.93 and practicality by teachers on field tests an average of 0.87 with a very high level of practicality. Hypothesis test results showed a significant difference between the learning outcomes of experimental class students and the control class in schools with moderate and low ability to use modules. Hypothesis test results also showed a significant difference between the critical thinking skills of experimental class students and the control class both in medium and low ability schools on the use of modules.

Keywords : Modules, Redox Reactions, Discovery, Probing Promting Techniques, Critical Thinking, Plomp Development Models