Social Sciences and History / Unit 10 SSH 0928 short lesson, about 20 seconds
Glaciers, Continental and Alpine
Captions available
The idea
Glaciers cover about ten percent of the land surface, near the poles and in high mountains; during ice ages they covered as much as thirty percent. Continental glaciers are ice sheets flowing outward over flat ground; alpine glaciers flow down mountain valleys.
In practice
The Snowball hypothesis: nearly all Earth once iced.
Where people slip
Geologists read where ice was from what it left.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
Unlocks
- Nothing yet depends on this.
Something wrong in this lesson? Flag it