Unit Two

2.1 Catastrophic Events

Vocabulary

catastrophic event: sudden and widespread disaster; a violent disturbance

flood: great flowing or overflowing of water over land

hurricane: huge, slowly-spinning tropical storm that forms over water and has winds of at least 119 km/hr (74 mph)

natural disaster: event or force of nature that has catastrophic consequences, such as earthquakes, flood, forest fire, hurricane, tornado, tsunami and volcanic eruption

tornado: small, destructive, whirling, fast-moving storm that forms over land

Videos:

2.2 Weathering, Erosion, Deposition

Vocabulary

abrasion: grinding away of rock by other rock particles carried in water, ice, or wind.

chemical weathering: wearing away of rocks by chemical processes, such as oxidation or dissolving

delta: landform made of sediment that is deposited where a river flows into an ocean or lake.

deposition: process by which wind, water and gravity leave eroded sediments in new locations

ecoregion: relatively large area that is characterized by distinctive plant and animal communities, climate, and ecological features.

erosion: movement of sediment by wind water, ice or gravity

frost wedging: process that splits rock when water seeps into cracks, then freezes and expands.

glacier: any large mass of ice that moves slowly over land

mechanical weathering: breaking up of rock by physical forces, such as the action of wind and moving water

runoff: water that flows over the ground surface without soaking into the ground

sediments: material that is broken down by processes of weathering, can be eroded and deposited by the agents of water, wind, ice, and gravity.

topography: description of land surface area with reference to elevation variations

weathering: breaking down of rocks

Videos:

2.3 Watersheds

Vocabulary

aquifer: layer of permeable rock through which water flows freely

drainage divide: a geographical barrier, such as a ridge, hill, or mountain separating one watershed land area from another

groundwater: water contained in the open spaces or pores of soil and rock

nonpoint source water pollution: pollutants introduced into surface or groundwater that are without a specific location source, such as water flowing over a lawn that has been fertilized and into a drain

permeability: description of how well a rock or sediment lets water pass through

permeable rock: allows water movement to flow through the material, the opposite of impermeable

point source water pollution: a single identifiable and localized source of water pollution, such as wastewater discharge into a stream

porosity: the volume of pore space available within rock or soil

runoff: water from rain or snow that flows over the surface of the ground into streams

saturation zone: below the water table where all spaces not filled with solid material fill with water

subsidence: sunken land surface due to underlying compression of earth material as a result of the removal of groundwater

surface water: water found on the surface of the Earth; includes rivers, lakes, streams, and oceans

watershed: area of land that drains water from higher land to lower land and into a stream; also called a drainage basin

water table: the top of the saturation zone, below which water fills all open spaces between the rock

zone of aeration: the upper portion of soil and rock that can be temporarily filled with water as the water enters the ground and moves deeper

Water Cycle