Professor Iain Stewart visits the Mortarach glacier in the Swiss Alps. Here, geologist Louis Agassiz gathered evidence in the 1830s to prove that glaciers moved downhill. Prof Stewart re-creates Agassiz's experiment and then shows modern evidence of movement using web-cam images. Stewart is lowered into a crevasse to show the scale of a glacier, then goes into an ice cave to examine boulders embedded in the glacial ice.
The evidence for how glaciers move is clearly shown and could be used to enhance any unit of the work of ice. Students could write how Agassiz discovered what causes ice to move. The clip could also be used to help describe how the availability of melt-water encourages movement and how boulders embedded in the ice scour the land beneath.