Looking
at the Earth
Objectives
Discuss
the five themes of geography.
Explain how the earth moves in space and why seasons change.
Describe the basic structure of the earth.
Chapter
Overview
Chapter 1: Looking at the Earth
Geography is the study of the earth and its people. Maps and globes are
some of the tools used to study the physical and human characteristics
of our planet. LANDSAT photos and Geographic Information Systems (GIS)
help geographers provide information used by government and business leaders
as they plan and make decisions.
Our planet, Earth, is part of a solar system made up of a sun, nine planets (*or is it 8 - What! No more Pluto!!! - or is it 12 or more!?!),
and thousands of smaller bodies. Life on Earth could not exist without
the heat and light provided by the sun or the atmosphere of gases that
surrounds the planet. The earth's rotation creates a twenty-four hour day
and night, while its orbit around the sun and 23 1/2 degree tilt produce
the seasons.
Inside the earth are layers of varying thickness and composition: the inner
core, outer core, mantle, and crust. Scientists theorize that volcanoes,
earthquakes, and continental drift are caused by the movement of tectonic
plates that float on top of the liquid rock in the mantle. The forces of
weathering and erosion also continually change the earth's surface.
People have adapted in order to live on various landforms. Mountains, plateaus,
valleys, and other landforms are found on land and under the oceans. About
70 percent of the earth's surface is water.
Quick Notes
Using the Geography Themes
Location tells you where a place is found.
Place tells you about the physical and human characteristics of a place.
Human actions have changed the environment, and the environment has forced
humans to adapt.
People, ideas, information and products move from place to place.
Geographers divide the earth into regions based on common physical or human
features.
Planet Earth
Earth, its moon, and other planets are part of our solar system.
The tilt of Earth on its axis and its revolution around the sun cause the
changes in seasons.
The rotation of Earth on its axis causes areas to have day and night.
Landforms
The earth has an inner and outer core, a mantle, and an outer crust.
Forces inside the earth, such as volcanic activity, create landforms.
Wind, water, and ice are surface forces that change landforms.
Major types of landforms include mountains, hills, plateaus, and plains.
The atmosphere is a cushion of gases that surrounds the earth.
*In August 2006 the International Astronomical Union (IAU) has proposed a new definition of a planet. The following pictures (Credit: IAU/Martin Kornmesser) visually show the 12 planets and other bodies that are being considered as planets (Space.com Article). UPDATE: As of August 25th it appearrs Pluto is no longer considered a planet, and is now a dwarf planet. What do you think of all of this!?!
1999-2006 © Hokanson's Social Studies
