The research aims to identify the impacts of embedding non-traditional writing tasks within the course of modern physics conducted to the students of Physics Education and Physics Study Programs. It employed a quasi-experimental method with the pretest-posttest control group design. The used instruments were tests on conceptual mastery, tests on critical thinking skills, and a rubric of writing assessment. The data were analyzed by determining the percentages of average normalized gains, Cohen's d, and correlational analysis. Based on the results of data analysis, it is found that the different treatments in the non-traditional writing tasks given to the students of the Physics Education and Physics Programs have the following impacts: 1. There was a significant difference in the increased conceptual mastery and critical thinking skills; 2. There was a difference in the writing quality of the students of the Physics Education and Physics Program; 3. There was a correlation between writing quality and conceptual mastery with a high degree relationship and there was a correlation between writing quality and critical thinking skills with a low degree relationship; 4. Increased conceptual understanding was influenced by the writing domain.