This is an excellent free PBS video about how scientists tracked down which volcano exploded in 1257 and caused a worldwide cold summer resulting in many deaths due to starvation. The video contains information about volcanoes themselves as well as a lot of information about how scientists study them. The scientific sleuthing that went on in this video is quite fascinating. This is a worksheet containing questions that can be answered by the students while watching the video to ensure they are paying attention.
The video can be streamed for free off the PBS website here: