In a rare move, I decided to post a second time today.  It is mostly because I have been feeling guilty about posting links to animations, videos, and interactive activities rather than posting lesson plans, lab activities, or classroom activities (the main goal of this blog).  So to fill the void, I am posting about an activity that can be done in the classroom for little to no cost. 

The website for the NASA Jet Propulsion Laboratory at the California Institute of Technology describes an activity in which each student demonstrates the phases of the moon in a simulation where the moon, sun, and earth are represented.  All you need is one light source (preferably a lamp), students, pencils, and some styrofoam balls.  The activity is short and straightforward helps students gain spacial awareness of the relationship between the sun, moon, and earth.