Chapters 1-6

• absolute humidity is the measure of the actual water vapor content of air expressed as the mass of water vapor in a given volume of air
• acid rain is the precipitation with a pH less than 5.6 which may involve dry deposition without moisture
• capillarity is the action by which water can climb upward in restricted confinement as a result of its high surface tension, and thus the ability of its molecules to stick closely together
• condensation is a warming process by which water vapor is converted into liquid water
• condensation nuclei are tiny atmospheric particles of dust, bacteria, smoke, and salt that serve as collection centers for water molecules
• dew is the condensation of beads of water on relatively cold surfaces
• dew point temperature is the critical air temperature at which water vapor saturation is reached
• the Antarctic Circle is the parallel of 66.5 degrees south latitude
• the point in earth's elliptical orbit at which the earth is furthest from the sun is aphelion
• the Arctic Circle is the parallel of 66.5 degrees north latitude
• the atmosphere is the gaseous envelope surrounding earth
• the biosphere is made up of the living organisms on earth
• the circle of illumination is the edge of the sunlit hemisphere that is a great circle separating earth into a light half and a dark half
• the cryosphere is the subsphere of the hydrosphere that encompasses frozen water (such as snow or ice)
• daylight-saving time is the shifting of clocks forward by one hour
• The December Solstice is the day of the year where the vertical rays of the sun strike the Tropic of Capricorn, occurring on or around December 21st
• The June Solstice is the day of the year where the vertical rays of the sun strike the Tropic of Cancer, occurring on or around June 21st
• the latitude receiving the vertical rays of the sun is the declination of the sun
• the Equator is the parallel of 0 degrees latitude
• geography is the study of distribution patterns in the landscape
• The Great Circle is the circle formed by the intersection of Earth's surface with any plane that passes through Earth's center
• Greenwich Mean Time (GMT) is commonly called Universal Time Coordinated (UTC)
• human geography is the study of the human and/or cultural elements of geography
• the hydrosphere is the total water realm of earth, including oceans, surface waters of the lands, groundwater, and water held in the atmosphere
• inclination is the tilt of Earth's rotational axis relative to its orbital plane (the plane of the ecliptic)
• the International Date Line marks the difference of an entire day from one side of the line to the other and falls on the 180th meridian
• latitude is measured north or south of the Equator
• the lithosphere is the part of the crust and upper ridgid mantle that comprises tectonic plates, and also refers to the entire solid earth
• longitude is measured east or west of the Prime Meridian
• the March equinox is one of two days of the year when the Sun's vertical rays strike the equator and every location on Earth has equal day and night, occurring on or around March 20th
• a meridian is an imaginary line extending pole to pole
• the North Pole is the latitude of 90 degrees north
• a parallel is a line collecting all points of equal latitude
• perihelion is the point in orbit where the Earth is closest to the Sun
• physical geography is the study of the physical or environmental elements of geography
• the plane of the ecliptic is an imaginary plane that passes through the Sun and Earth at every position in its orbit
• polarity is a characteristic of Earth's axis where it always points towards Polaris (the North Star) at every position in Earth's orbit around the sun
• the Prime Meridian is the meridian passing through the royal observatory at Greenwich from which longitude is measured
• Earth's orbital movement around the Sun is known as a revolution
• the spinning of Earth about its axis is known as its rotation