The purpose of this study was to investigate empirically the application of one of the cornerstones of chaos theory, that is, sensitivity to initial conditions, to language assessment. In doing so, 20 Iranian students at masters’ level participated in this study. They were majoring in nanophysics in Islamic Azad University of Bushehr. They were sophomores aged 23 to 30. In order to ensure homogeneity, they were administered a test of reading comprehension called PET. Then, another test of reading comprehension was administered to them based on “English for the Students of Physics”. Having taken that test, the students took the same test after two weeks in different versions. The versions were created by changing the order of items. The analysis of the data showed that 75.83% of students performed better in the second version of the test. This showed the effect of changing the order of items on the students’ performance which is consistent with the principle of sensitivity to initial conditions in chaos theory. The implications of the findings will be discussed at the end of the study.