We present a MATLAB script INSOLATE.m that calculates insolation at the top of the atmosphere and the total amount of daylight during the year (and other quantities) with respect to geographic latitude and Earth's obliquity (axial tilt). The script output displays insolation values for an entire year on a three-dimensional graph. This tool facilitates classroom discussion of broadly based concept questions regarding the effect of insolation on seasonality and climate. It can be used to demonstrate insolation patterns and changes that apply to a wide range of sciences, including climatology, biology, ecology, planetary science, and green engineering. Students who used the script in class assignments in an introductory level Earth science course showed an overall 32% improvement in scores on associated test and quiz questions compared with students who did not use the script to demonstrate the effects of obliquity and latitude on insolation.