Introduction to “Why? The Earth” … 3
Samcheongapja Dongbangsak, 180,000 Years Old … 8
The Earth is Round … 12
How Did the Earth Come into Existence? … 19
How Did Land and Ocean Come into Existence? … 22
The Appearance of the First Organism-Precambrian Era … 26
What Kind of Organisms Lived in the Paleozoic Era? … 30
The Mesozoic Era-the Era of Dinosaurs … 32
The Cenozoic Era, When Human Ancestors First Appeared … 34
The History of the Earth in the Strata … 36
Dongbangsak’s Past … 38
Moving Continents … 42
The Earth’s Main Axis-the Mantle and the Core … 49
Volcanic Eruptions-the Earth’s Fireworks … 52
The Features of a Volcano … 58
Why Do Earthquakes Occur? … 60
What to Do in an Earthquake … 64
Mythical Continents … 68
Orogeny, the Process of Mountain Formation … 70
The Life of a Mountain … 74
The Shape of Korea … 76
What Makes Up the Crust … 78
Meandering Rivers-Erosion … 81
How Strata are Formed … 83
Fossils-Treasures Buried in the Strata … 86
Petroleum and Coal-Valuable Underground Resources … 90
Sedimentary Rocks-Layers of Rocks … 92
Igneous Rocks-Rocks Formed by Volcanoes … 94
Metamorphic Rocks-Rocks with Changed Properties … 96
Rocks That Change Due to Weathering … 100
From Rocks to Soil-The Power of Organisms … 102
Deserts-Dry Land … 106
The Circulating World of Water … 109
The Power of Water to Change Topography … 111
Subterranean Water Flows, Too … 116
Going on a Cave Exploration … 120
Hot Springs and Geysers … 123
Mountain Ranges Exist Even in the Ocean … 126
Why Does Seawater Move? … 132
What is a Trench? … 137
The Arctic and the Antarctic … 139
Our Incredible Earth … 144
The Earth is Hurting … 150
Only One Earth … 155