Chapter 5, Lesson 1
Landform: physical features of Earth’s surface
See page 241 for list and definitions
Ocean Basin: large underwater area between 2 continents
Continental Shelf
Continental Slope
Continental Rise
Seamount: underwater mountain
Trenches: deepest part
Abyssal Plain: wide and flat; 40% of ocean
Surveyor: person who measures land
Elevation: height of land
Relief Map: uses shading to show levels
Topographical Map: uses lines to show levels
Earth’s Layers
Atmosphere: gases around Earth
Hydrosphere: all of Earth’s liquid (70% of surface)
Lithosphere
Crust: rocky layer; continents and ocean basins
Top of upper mantle: solid rock
Asthenosphere
Rest of upper mantle; melted rock
Lower Mantle: solid rock
Outer Core: liquid metals
Inner Core: solid metals
*Biosphere: areas that support living things; lower atmosphere to ocean floor
Chapter 5, Lesson 2
Geologist: studies rocks to find out about Earth’s history and structure
Theory of Continental Drift: continents were once together (Pangaea) and have drifted apart
Evidence includes: mountains between South America and Africa match
Fossils
Coastlines
Plate Tectonics: model to explain how ocean floor spreads and continents move
Compression: squeezing together; creates folded mountains (Himalayas)
Shear: a result of one plate rubbing against another causing twists or tears in crust
Fault: a deep crack in crust;
if one moves up and other down result is a fault block mountain (Sierra Nevada)
Chapter 5, Lesson 3
Volcano: opening in Earth’s crust; most found where plates meet (usually where 1 plate is
pushed under another…diving plate melts in the heat of the mantle and forms magma)
Ring of Fire: circle of volcanoes around the Pacific Ocean
Lava: magma which reaches the Earth’s surface
Crater: depression formed around a vent
Caldera: hole formed when volcano collapses on itself
Dike: formed when magma hardens in vertical cracks
Sill: forms when magma hardens in horizontal cracks
Laccolith: magma pushed into sills; dome shape that raises rock layers above it
Batholith: largest underground magma formation; form hills
Active: erupting or recently erupted
Dormant: quiet for a time
Extinct: no longer erupts
Shield Volcano: built by thinner fluid lava that spreads over large area; broad base, sloping sides
Cinder-cone Volcano: thick lava thrown high into the air and falls as chunks or cinders;
Cone shaped with narrow base and steep sides
Composite Volcano: built by layers of ash and cinders sandwiched between hardened lava;
Look the same on both sides.
Hawaiian Islands are a line of volcanic mountains.
Formed over a hot spot; when they grew tall enough they became islands
Hot spot: stationary pool of magma
Island Arc: where two ocean plates meet and one is pushed under another (Aleutian Islands)
Chapter 5, Lesson 4
Earthquake: sudden movement of Earth’s crust usually along a fault line at the boundary of
tectonic plates
Focus: place where slipping begins
Epicenter: point on Earth’s surface directly above the focus
Seismometer: instrument that detects and measures waves produced by earthquakes
Primary (P) waves: fastest; pass through solid and liquid layers; move back and forth
Secondary(S) waves: half as fast; only through solid layers; move up and down
Surface (L) waves: slowest like ripples on a pond; on Earth’s surface; cause most damage
Magnitude: amount of energy released by an earthquake
Richter Scale: used to measure magnitude (each whole # indicates 30 x more energy)
Mercalli Scale: measures what people felt and what happened to objects (more real life)
Aftershocks: earthquakes with less magnitude
Tsunami: huge wave caused by earthquake in the ocean; generally 6.5 or higher
Buildings now have rubber and steel between foundation and building to allow the building to
sway without causing damage.
If you have warning furniture should be secured to walls.
Scientists try to predict quakes by looking at changes in angle of the ground.
They are very difficult to predict.
Chapter 5, Lesson 5
Weathering: the process by which rocks are broken down
Physical Weathering
Temperature changes
Pushing and pulling
Water freezing and expanding cracks
Plants growing and increasing cracks
Gravity
Wind
Chemical Weathering
Groundwater
Acid Rain: formed by gases from factories combine with rain
Erosion: weathered rock is moved from one place to another
Gravity: mudslides, landslides
Glaciers: large mass of flowing ice; as glacier moves it carries away bits of rock;
Cirque: steep bowl shaped hollow at edge of glacier
Deposition: eroded materials are dropped off in another place
Rivers erode rock and soil and wash it downstream.
Meanders: slow moving curved rivers
Delta: fan shaped area at mouth of river
Sandbars: created by waves carrying sand offshore
Barrier islands: sandbar that stretches miles and protects shoreline
Dunes: formed by wind at the back of beach; protect area farther inland
Fences and plants can be added to protect dunes
Floodplain: place that is easily flooded when river rises and sediment is deposited here
Wetlands soak up water and reduce chance of flooding
People can also control some erosion by building dams, levees (walls), and canals.