SPS interns Mary Mills, Justin Reeder, Jenna Smith, Meagan Saldua, and Logan Hancock conducted classroom demonstrations at Yorktown High School in Yorktown, VA, Wednesday June 11, 2008.

In the first photo, Jenna explains to the class that the two crossed polarizers are exactly like the spring and the PVC poles (not pictured) they had been playing around with. When you cross two polarizers perpendicularly, the light is block out completely. Logan holds one end of the slinky and makes waves as the students use PVC poles as “polarizers” to block the waves on the slinky.