Latitude
East/West lines that determine North/South locations.
Longitude
North/South lines that determine East/West locations.
Tropic of Cancer
23.5 Degrees North, the northernmost point on Earth that experiences the direct rays of the sun.
Tropic of Capricorn
23.5 Degrees South, the southernmost point on Earth that experiences the direct rays of the sun.
Arctic Circle
66.5 Degrees North, the farthest point from the North Pole, in the northern hemisphere, that experiences at least one day when the sun does not rise and at least one day when the sun does not set.
Antarctic Circle
66.5 Degrees South, the farthest point from the South Pole, in the southern hemisphere, that experiences at least one day when the sun does not rise and at least one day when the sun does not set.
International Dateline
Line marking the point where each day ends and begins.
Maps
Primary tool of the geographer, a scaled representation of all 4 portions of the Earth's surface.
Graphic Scale
A method of scale representation on a map using a visual graphic.
Stated Scale
A method of scale representation on a map using a written statement.
Representative Fraction (RF)
A method of scale representation on a map using a ratio.
U.S.G.S
United States Geological Survey, in charge of overseeing any geological issue in the country.
Small Scale Maps
Show a lot of area with little detail.
Large Scale Maps
Show a little area with a lot of detail.
Planimetric Maps
Show two-dimensional information only, no reference to altitude.
Thematic Maps
Present a theme or topic, useful in presenting geographic information.
Topographic Maps
Show three-dimensional information, including altitude values.
Map Projections
The way that the surface features of the Earth are projected onto the map surface.
Great Circle
Any line which bisects the Earth into two equal half spheres.
The Universe
All things, the study of which is called cosmology.
Astronomy
The study of space.
Speed of Light
186,000 Miles Per Second, the distance that light will travel in one year's time.
The Light Year
The distance that light will travel in one year's time, approximately 6,000,000,000,000 miles.
The Big Bang
Occurred between 13.6 - 14.0 billion years ago, the event that marked the beginning of the universe.
Galaxies
Organized groups of stars, such as the Andromeda Galaxy.
Formation of Planets
The process by which planets are formed, including the Proto Earth and the Terrestrial and Jovian planets.
The Solar System
The system of planets, asteroids, comets, and other celestial bodies that orbit around the Sun.
Asteroids
Pieces of space rocks, found in the Asteroid Belt.
Comets
Celestial bodies made of ice, dust, and gas, such as Comet Hale-Bopp and Comet 67P.
Meteor
A small celestial body that enters the Earth's atmosphere and burns up, also known as a shooting star.
Size and Shape of the Earth
The dimensions and relief of the Earth, including the Equatorial and Polar Diameters.
Relief
The difference in altitude between the highest and lowest points of an area or region.
Types of Terrain
Different types of landforms, including Low Relief, High Relief, and High Rugged Relief.
Movements of the Earth in Space
The rotation and revolution of the Earth, including the speed and periods of each.
The Seasons
The changes in weather and temperature caused by the Earth's revolution and inclination to the ecliptic.
Constellation
An arbitrary grouping of stars that serve as reference points in the night sky.
Sun's Energy
The energy produced by the Sun through nuclear fusion, including the electromagnetic spectrum and the composition of the Sun's energy.
Distribution of Insolation
The distribution of incoming solar radiation, including the percentage of insolation absorbed, wasted, and distributed by clouds and surface.
Composition of the Atmosphere
The primary and trace gases that make up the Earth's atmosphere, including nitrogen, oxygen, carbon dioxide, and water vapor.
Structure of the Atmosphere
The layers of the Earth's atmosphere, including the troposphere, stratosphere, mesosphere, and thermosphere.
Weather
The condition of the atmosphere with respect to the weather elements for a short period of time.
Climate
The range of weather possibilities and probabilities for long periods of time
Mercurial Barometer
A barometer that uses mercury air pressure to measure atmospheric pressure.
Aneroid Barometer
A barometer that uses a small capsule with flexible sides and no air to measure atmospheric pressure.
High Pressure Centers
Also known as anticyclones, these are areas of high atmospheric pressure that generally result in fair weather.
Low Pressure Centers
Also known as cyclones, these are areas of low atmospheric pressure that generally result in poor weather.
Wind
Air in motion, measured in terms of speed and direction.
Anemometer
An instrument used to measure the speed of the wind.
Wind Vane/Weather Vane
An instrument used to show the direction from which the wind is blowing.
Pressure Gradient
The difference in pressure between high and low pressure areas, which affects wind speed.
Coriolis Force
The deflection in the course of a moving object, such as gases and fluids, caused by the rotation of the Earth.
Trade Winds
The wind system that blows between the subtropical highs and equatorial lows, covering a large surface area.
Westerlies
The wind system of the temperate world, including the conterminous United States, where most weather systems come from the west.
Polar Easterlies
The weakest of the major surface wind systems, blowing between the polar highs.
Equatorial Low
A region of low pressure near the equator, characterized by strong winds and thunderstorms.
Monsoon
A seasonally reversing wind flow system, resulting in a rainy summer and a dry winter in South and Southeast Asia.
Jet Stream
A high-speed, narrow air current that serves as the steering current for surface weather disturbances.
Humidity
The general term referring to the moisture in the air.
Relative Humidity
The ratio of the amount of water vapor actually in the air to the maximum amount it can hold at a given temperature, expressed as a percentage.
Dew Point
The temperature at which relative humidity reaches 100% and condensation occurs.
Precipitation
Water falling from the atmosphere in various forms, such as rain, drizzle, snow, sleet, and hail.
Rain Gauge
A meteorological instrument used to measure the amount of rainfall over a specific area during a specified period of time.
Hydrologic Cycle
The continuous path of water from the Earth to the atmosphere and back to the surface, replenishing our water supply.
Aquifers
Underground layers of permeable rock or sediment that hold water.
Clouds
Visible masses of water droplets or ice crystals suspended in the atmosphere.
Cumulus Clouds
Puffy clouds with flat bottoms that represent the atmospheric dew point.
Cirrus Clouds
High altitude clouds made up of ice crystals, usually preceding a warm front.
Cumulonimbus Cloud
A dense, towering vertical cloud that forms from water vapor condensing in the lower troposphere, associated with thunderstorms.
Contrails
Condensation trails formed by jets, resulting from the rising air characteristics.
Orographic Lifting
The rising of air over high mountains.
Frontal Lifting
The rising of air over weather fronts, where warm air rises relative to cold air.
Convectional Lifting
The spontaneous rising of heated air.
Cyclonic Lifting
The upward spiral of air into the low of a well-developed storm, characteristic of tornadoes and hurricanes.
Latitude
The distance from the equator, affecting precipitation distribution due to pressure belts.
Continentality
The location within a continent, affecting precipitation due to proximity to oceanic water vapor sources.
Ocean Currents
The temperature of the water in the current affects the temperature of the air above it, influencing precipitation patterns.
Mountain Barriers
High mountains that create a rainshadow effect, resulting in wetter windward sides and drier leeward sides.
Isohyet
Lines connecting points of equal precipitation on a precipitation map.
Precipitation Variability
The extent to which precipitation varies from month to month and year to year, influencing agricultural practices worldwide.
Air Mass
A large body of air with uniform temperature and moisture characteristics.
Cold Front
The leading edge of a cold air mass that moves into a region of warm air.
Warm Front
The leading edge of a warm air mass that moves into a region of cold air.
Occluded Front
Occurs when a cold front catches up to and merges with a warm front, marking the end of a midlatitude cyclone.
Stationary Front
A front where air masses and fronts stop moving, resulting in little to no change in weather conditions.
Maritime Tropical
An air mass characterized by warm and moist conditions, typically originating over tropical oceans.
Maritime Polar
An air mass characterized by cool and moist conditions, typically originating over polar oceans.
Continental Polar
An air mass characterized by cold and dry conditions, typically originating over polar land areas.
Hurricane
A well-developed whirl of air around a calm eye, typically forming in tropical oceans between 6 and 30 degrees latitude.
Storm Surge
The most damaging aspect of a hurricane, referring to the rise in sea level caused by the storm's winds and low atmospheric pressure.
Tornado Alley
A region in the central United States and Canada where tornadoes are most frequent.
Fujita Scale
A scale used to rate the intensity of tornadoes based on the damage they cause.
Squall Line
A line of severe thunderstorms that can form along or ahead of a cold front, often associated with strong winds, heavy rain, and tornadoes.
Air Mass Modification
The process by which air masses change their characteristics as they move, such as a cold air mass becoming warm or a dry air mass becoming wet.
Climate Classification
The categorization of long-term patterns of temperature, humidity, wind, precipitation, and other atmospheric conditions in a particular region.
Koppen System
The most widely used climate classification system, which identifies a dozen major climate groups and their respective climate types.
Climograph
A graphical representation of climate data, showing the average monthly temperature and precipitation for a specific location.
Paleoclimatology
The study of prehistoric climates, often using methods such as tree ring analysis, oxygen isotope analysis, and radiocarbon dating.
Geologic Time
The age of the Earth, estimated to be around 4.6 billion years.
Geologic Time Scale
A timeline that divides Earth's history into different periods and epochs based on major geological and biological events.
Continental Drift
The theory proposed by Alfred Wegner that suggests the continents were once joined together as a supercontinent called Pangea.