In this activity, students use a digital microscope to capture salt crystal formation using time-lapse photography. Through analysis of the time-lapse video clips of both slow and fast evaporation, students identify differences in the size and appearance of two salt crystal samples. Conclusions from this activity can be applied to the formation of intrusive and extrusive igneous rocks. 

The object of this lesson is for students to develop understandings of the role of cooling time in the development of crystals through an inductive, hands-on activity.