This study aims to obtain a valid scientific-based physics learning module to improve critical thinking skills in Dynamic Fluid material for high school/MA students. This study uses a research development design and approach or is included in development research. In this study, a scientific-based physics learning module was developed. The development of this module refers to the development of the (4-D model) proposed by Thiagarajan. This model consists of 4 development stages, namely (Define, Design, Develop, and Disseminate). However, this study is only limited to the development stage, namely the validation stage. The validation test is a theoretical validation. Namely, assurance carried out by experts in their fields. The confirmation includes material, media, language, teacher and peer validation. The research results found that the physics-based learning module was scientifically based on improving critical thinking skills in Dynamic Fluid material for high school / MA students, which were developed to meet the validity criteria. In conclusion, the physics-based learning module to improve critical thinking skills in Dynamic Fluid material for high school / MA students is very well developed.