This study examined changes in the quality of written arguments produced by freshman students in general chemistry laboratory classes using the SWH approach over a semester; difference in the quality of written argument between the original writing template (year I) and the extended writing template (year II); and any difference between Total Argument and Holistic Argument scores. 140 writing samples from 14 students on the year I and 228 samples from 19 students on the year II were collected. Results indicated that despite fluctuations, the students were producing stronger argument by the end of semester compared to the beginning of the semester. Original SWH template group received significantly higher argument scores than extended SWH template group. For the most of year I laboratory investigations, there was no significant difference in the quality of argument between Total Argument and Holistic Argument scores. An implication of this study would be to provide opportunities for students to practice constructing arguments using the original SWH writing template including questions, claims, evidence, and reflection.