Things that BUILD UP and TEAR DOWN the Earth…

Constructive Forces the process of building up the Earth’s surface

Destructive Forces the process of breaking down the Earth’s surface

Sand Dunes a ridge of sand created by the wind

Delta the area where a river empties out into a larger body of water

Cave a hollow or natural passage under or into the Earth

Canyon a deep valley with steep sides, often has a stream at the bottom

Levee a barrier built to keep the flow of water out

Glacier a slow moving mass of ice