Environmental Science

Earth-Sun Relationships The Sun is the source from almost all of the Earth?s weather and climate. Earth intercepts 12000000000 (one two-billionth) of all the energy given off by the sun (this is several hundred thousand times the energy generation of the US). Solar energy isn?t evenly distributed; the amount of energy varies with latitude, time of day, and season. Unequal heating of Earth creates winds and ocean currents, which transport heat to balance energy inequalities; the consequences of these processes are called weather. If the Sun died, global winds and currents would stop; but if the Sun shines, the winds will blow and weather will exist. Variations in solar heating are caused by the motions of the Earth relative to the Sun and variations in the Earth?s land-sea surface.

Vertical Structure of the Atmosphere A. Pressure Changes Atmospheric Pressure: weight of the air above - at sea level, the avg. pressure ~ 1000 millibars (mb), or ~ 1 kg/cm2 Pressure at higher altitudes is less ? of the atmosphere is below 5.6 km (3.5 mi); at 16 km (10 mi), 90% of the atmosphere has been passed, and > 100 km (62 mi), only 0.00003 % of all gases in the atmosphere remain. Rest of atmosphere merges with space vacuum. B. Temperature Changes Near Earth?s surface, air temperature drops with an increase of height. I. Troposphere (air ?turns over?) Lowermost atmosphere layer (we live in here); temperature decreases with an altitude increase. All important weather occurs here.

Creating a Time Scale: Relative Dating Principles A. Importance of a Time Scale Rocks record geological events + changing life forms of the past; however, many pages (especially earlier ones) are missing or incomplete. Geologiests can unravel complexity of the past Earth by studying rocks Geologic events have little meaning until put into perspective. Geologic time scale = major contribution of geology (Earth?s age = huge) B. Numerical and Relative Dates Geologists have learned that Earth is much older than people thought, and it has been changed over and over again by the same geologic principles I. Numerical Dates

Transform Plate Boundaries In a transform plate boundary (transform fault), plates slide horizontally past one another without producing or destroying lithosphere. They commonly connect 2 spreading centers (divergent), or less commonly 2 trenches (convergent). Mostly found on ocean floor (offset segments of oceanic ridge system, producing a steplike plate margin). Zigzag shape of Mid-Atlantic Ridge reflects shape of original shape of rifting Transform faults are part of linear breaks in seafloor (fracture zones) that include active and inactive (extensions) of the transform faults.