2. Earth’s Balancing Act Forces generated by the Earth and the Sun affect land, sea and air to drive our dynamic planet. This complex interplay can also unleash catastrophic natural disasters.
3. A Dynamic Earth All living things exist in a zone delicately balanced between two immensely powerful engines – the molten core of the Earth itself and the blazing Sun. Each generates a host of forces, setting off the earthquakes, volcanoes, and extremes of weather that shape our lands and seas.
4. The Moon The MOON - On the side of the Earth facing the Moon, gravity pulls the ocean outward, creating high tides. Inertia on the opposite side of the planet has the same effect.
5. Solar Energy – Earth should release into space the same amount of energy it absorbs from the Sun. Greenhouse gases accumulating in the atmosphere upset that balance by blocking energy release. The Sun Solar energy intake 100% The Sun – A great ball of turbulent gases, our star supplies the heat and light needed to support life. Hydrogen atoms combine to make helium, producing an internal temperature of about 28,080,000°F.
6. Atmosphere The Atmosphere – A fragile layer of gas, the atmosphere protects our planet from the sun’s radiation and other hazards. Stirred by the Earth’s rotation and shifts in pressure and temperature, the atmosphere changes constantly, causing what we experience as weather.
7. Atmospheric Cells Atmospheric cells – In constant loops, air warmed by the sun in the tropics flows to the poles as cold polar air travels to the tropics.
8. Hurricanes Hurricanes – Fueled by warm ocean water, hurricanes begin to spin at more than 74 miles per hour. Heavy rains and an elevated sea surface add to the danger. Cool Air Warm, Humid Air
10. The Ocean The ocean – covering more than two-thirds of the planet, the ocean interacts with the atmosphere to make Earth habitable. Its currents distribute heat absorbed in the tropics to northern lands that would other wise be icy year round.
11. Ocean Currents Ocean currents – Evaporation, precipitation, cooling, heating, wind, up-welling, and other forces move water at the surface and stir deep circulation.
12. Tsunamis Tsunamis – Large disturbances of the seafloor – especially earthquakes – create towering waves that can devastate the coastal communities they strike.
14. CINDER CONE Crater The simplest volcanoes, cinder cones form when eruptions shoot particles of gassy lava into the air that solidify in flight and rain down around the vent, eventually creating conical peaks. Central Vent
15. SHEILD VOLCANOES Lava flowing out in all directions from a central vent gives shield volcanoes their distinctive gentle slopes and enormous breadth. Some, like Hawaii’s Mauna Loa, are dozens of miles wide.
16. COMPOSITE VOLCANOES Like cone-shaped layer cakes, volcanoes such as Mount Fuji and Mount Rainer are made up of alternating layers of ash, lava, and rocks created by multiple – and often explosive eruptions.
17. Earth Some 4.6 billion years ago, a dust cloud condensed to create our planet. Layers formed as it began to cool. Continual internal roiling moves heat the surface for release.
18. Tectonics Rigid slabs of Earth that make up the Earth’s surface. The underlying rock is viscous, circulating in vast convection currents that slowly grind the slabs against each other.
19. Earthquakes When two slabs of crust crunch punch into each other or one dives beneath the other, the ground shakes – sometimes violently. trench Down-going tectonic plate
