Abstract
The study aims at identifying the ability of mental rotation, according to gender and rotation angle, among a sample of Al-Qassim university postgraduates enrolled in first, second, third and fourth years and majoring in mathematics. The sample consisted of (160) student randomly assigned to the mental rotation test. The study utilized a mental rotation computerized test (Classmaker) to measure student's ability, the test included (144) tasks. Six stimuli are used; each one is represented by two 3-Dimentional shapes, each stimulus is rotated (24) times, (12) with and (12) counterclockwise. Identical shapes following rotation were (72) and non-identical shapes were (72) according to the rotation angles (30˚, 60˚, 90˚, 120˚, 150˚, 180˚). Validity and reliability of the test were insured. Results proved that mental rotation ability increased by the academic year increase, the correct answers number increased and the reaction time decreased. Results also showed that when the rotation angle is larger the correct answers number decreased, and significant differences appeared in reaction time due to the rotation angle. No significant differences were found in the relationship between the gender and means of the reaction time.