The reason Stephen Morris studies icicles is simple. They are common and beautiful, and they make you wonder. And they are now documented online in all their chilly, wet glory in the Icicle Atlas.

Dr. Morris, a University of Toronto professor who created the atlas, is a physicist who probes the subtle underpinnings of the kinds of obvious physical phenomena people see every day.

“Being Canadian,” he said, “I see a lot of icicles.”

But not enough. And not created in controlled conditions. He recruited a graduate student, Antony Chen, now an instructor at the Southern Alberta Institute of Technology in Calgary. Dr. Chen produced “the most elaborate study of icicle morphology ever done,” Dr. Morris said.