Glaciers are essentially rivers of ice. These landforms occur in areas where accumulated snow collects faster than it can melt away each year. Over time this perennial snow packs down into hard, blue glacial ice. As the ice accumulates, it gets thicker and heavier, until gravity begins to pull the ice sheet downhill. Precipitation continually feeds the top of the glacier with snow and ice as the glacier flows downhill, much like a river.
The great weight of glaciers causes the ice to grind away at nearby rocks to form a fine sediment called called rock flour, and large rocks from the valley and canyon walls as it moves. In this experiment we use shaved ice to demonstrate what's in a glacier and see how rocks deposits are formed up when a glacier melts, from sugary fine rock flour to large boulders.