The Physical World

Chapter 2

Chapter 2, Section 1: Planet Earth• Our Solar System• The Planets• Asteroids, Comets, and Meteoroids

• Earth• Water, Land, Air• Landforms• Earth’s Heights and Depths

The Solar System

Terrestrial planets Gas giant planets

Asteroid Belt

Kuiper Belt (Ice and Pluto)

All of this is surrounded by the Oort Cloud

Asteroids, Comets, and Meteroids• Comets are icy clumps of dust• Meteoroids are pieces of space debris• Meteors are shootings stars (burning in the

atmosphere)• Meteorites are the meteoroids that hit the Earth

Water, Land, and Air• Water = hydrosphere• Land = lithosphere• Air = atmosphere• Life = biosphere

(Now I draw)

Landforms, Heights and Depths• The natural features of the Earth’s surface (water included)• A continental shelf is an underwater extension of the

coastal plain

• Mount Everest is the highest point of Earth• The shore of the Dead Sea is the lowest dry point on earth• The Mariana Trench is the actual lowest pointon Earth

Chapter 2, Section 2: Forces of Change• Earth’s Structure• Internal Forces of Change• Plate tectonics• Folds and faults• Earthquakes and volcanoes

• External Forces of Change• Weathering• Erosion• Soil Building

Earth’s Structure• Earth is like an ogre• Earth’s layers are:• Crust• Mantle• Outer Core• Inner Core

Pangea• The theory that the continents were all once

connected and then slowly drifted apart is called continental drift• The movement of plates = plate tectonics• Plates move because they are more or less floating on

magma

Forces of Change

•3 Ways Plate Tectonics Work•Convergent (Subduction)•Divergent (Spreading)•Faulting (Transform)

Convergent (Subduction)• A heavier sea plate dives beneath a continental plate

lighter plate• This is a cause for the formation of volcanoes and

volcanic eruptions• Earthquakes

Divergent (Spreading)• Two sea plates pull apart• Earthquakes

Iceland

Faulting (Transform)• Two plates slide against each other in opposite

directions, like a highway• Faulting occurs when the folded land cannot be bent

any further• Earthquakes

San Andreas Fault (California)

Earthquakes• Earthquakes are a direct reaction to plate tectonics• Earthquakes (strong ones too) are relatively common

on the West Coast and Japan (San Francisco, Los Angeles, Kobe)• This is because these places are located along the

Ring of Fire, one of the most earthquake-prone areas on the planet

External Forces of Change• Weathering: Wind and water breaks down rocks• Erosion: Wind, water, and glaciers wears away the Earth’s

surface• Wind Erosion: when wind wears away the Earth’s surface• Water Erosion: when water wears away The Earth’s surface• Glacial Erosion: when glaciers wear away the Earth’s surface (+

Greenland, Antarctica)

• Soil Building: Wind, temperature, rainfall, biology, etc. determine the type of soil that can develop • Rivers moving soil downstream• Worms, living and dead plants (and animals)• Etc.

Is this an example of erosion or weathering?

Chapter 2, Section 3: Earth’s Water• The Water Cycle• Evaporation• Condensation• Precipitation

• Bodies of Salt Water• Oceans• Salt Water to Freshwater (Desalination through Distillation)

• Bodies of Freshwater• Lakes, streams, and rivers• Groundwater

The Water Cycle

Evaporation: liquid waterchanges into vapor, or gas

Condensation: Warm air cools, water vapor changes into liquid water

Precipitation: when cloudsgather more water than theycan hold, it rains, snows, or sleets

Bodies of Saltwater: Oceans• About 97% of Earth’s water consists of a huge,

continuous ocean that circles the planet• This continuous body of water is divided into five

oceans:• Pacific• Atlantic• Indian• Arctic• Southern (Might as well be called the Antarctic Ocean)

Bodies of Salt Water: Seas, Gulfs, and Bays• Seas, gulfs, and bays are bodies of salt water smaller

than oceans• They are often partially enclosed by land• Mediterranean Sea is almost entirely encircled by southern

Europe• Gulf of Mexico is nearly encircled by the coasts of the USA

and Mexico

Study This (and the orange circles)

Salt Water to Freshwater• Desalination: turning ocean water into freshwater

But this is very expensive

Bodies of Freshwater• Lakes, streams, and rivers• You know what a lake is. Streams are smaller rivers.• Groundwater: freshwater that lies beneath the

Earth’s surface• Groundwater comes from rain and melted snow• We obtain groundwater through springs and wells

• Aquifer: An underground porous rock layer saturated by flows of water