The use of resistivity meters to model subsurface conditions is widespread. However, commercial instruments are mostly limited to conventional configurations, such as Wenner, Schlumberger, and dipole-dipole. Moreover, we cannot modify the program on the instrument. In this study, we designed and implemented a DC resistivity meter that can potentially be developed in the future and can be used in composite array configurations. This instrument uses a half-bridge SMPS as a power supply, which is capable of generating a large power, an Arduino Uno, and several sensor modules as part of a flexible and easy-to-program control unit. We conducted laboratory and field tests, comparing two types of configurations, namely Wenner and composite arrays (dipole-dipole and gradient). We then processed the data using ResIPy software, which enables displaying complex data sets in the form of 2D cross-sections and assessing the quality of post-processing data. We obtained good data with low RMS misfit that matched the synthetic media created in laboratory testing and compared well with previous research.

This study aimed to produce a teaching material product as a companion book based on a feasible and practical problem-solving approach to increase students' understanding of natural sciences on forms and energy sources. Understanding the material taught to students is not fully understood, as can be seen from the acquisition scores obtained by students who are still below the minimum completeness criterion of 70. This research method is development or Research and Development adapted from the ADDIE development model, which consists of five stages, namely: 1) Analysis Phase (Analyze); 2) Design Stage (Design); 3) Development Stage; 4) Implementation Stage (Implementation); and 5) Evaluation Stage. The research subjects were class IV MIS As-Shofiah using a nonprobability sampling technique (purposive sampling) of 3 students with the provisions of the highest student learning outcomes, average scores, and lowest scores with the hope that they could represent all students in class IV A. The instruments were questionnaires and questions. The results showed that the developed teaching materials fall into the "Very Good" criteria by obtaining a score of 100% from material experts, 86% from design experts, and 98% from student responses to using advanced teaching materials. The results of teaching materials trials related to material understanding were carried out in class IV students by obtaining an average pretest score of 46.25 and an average posttest score of 90.