Earth Science

An aquifer is a permeable body of rock or sediment that stores and transmits groundwater in usable quantities.

Earth’s atmosphere is the gravitationally retained envelope of gases that supports life, produces weather, and regulates exchanges of heat and moisture.

The carbon cycle is the movement and transformation of carbon among Earth’s atmosphere, organisms, oceans, soils, sediments, and rocks.

A mass extinction about 66 million years ago, driven principally by an asteroid impact, that eliminated non-avian dinosaurs and many other organisms.

The cryosphere comprises Earth’s snow, ice, and frozen ground, influencing climate, freshwater availability, sea level, and ecosystems.

A drainage basin is the land area that directs surface water toward a common outlet or an internally drained depression.

Earth’s energy budget describes incoming solar energy, outgoing radiation, internal heat transfers, and energy storage within the climate system.

Erosion is the removal and movement of rock, soil, and sediment by water, wind, ice, and related surface processes.

A partially enclosed coastal water body where freshwater and seawater mix, supporting distinctive habitats and linking river basins with the ocean.

Evapotranspiration is the combined transfer of water to the atmosphere through evaporation from surfaces and transpiration by plants.

A floodplain is low-lying land beside a river, shaped by channel movement and sediment deposition and subject to periodic inundation.

Geology studies Earth’s materials, structure, processes, and history through evidence preserved in rocks and other geological records.

A glacier is a persistent mass of land-based ice that forms from accumulated snow and flows under its own weight, shaping landscapes and storing freshwater.

Groundwater is water stored and moving within saturated rock and sediment beneath the land surface, supplying wells, sustaining ecosystems, and connecting with surface waters.

The hydrosphere comprises Earth’s water in liquid, solid, and gaseous forms, linking oceans, land, atmosphere, and living organisms.

An ice core is a cylindrical sample of glacier or ice-sheet ice that preserves evidence of past climate, atmospheric composition, and environmental conditions.

Krakatoa is a volcanic complex in the Sunda Strait between Java and Sumatra, best known for its catastrophic 1883 eruption that killed more than 36,000 people.

A naturally occurring, usually crystalline inorganic solid with a defined chemical composition; minerals form rocks and supply most raw materials.

The ocean is the continuous body of salt water covering about 71% of Earth's surface. It holds most of the planet's water and shapes its climate and life.

Paleontology studies the history of life through fossils, reconstructing ancient organisms, evolutionary relationships, environments, and changes across geological time.

Permeability measures how readily a porous material transmits fluids through its connected pores and fractures.

Plate tectonics explains how moving lithospheric plates reshape Earth through seafloor spreading, subduction, continental collision, and faulting.

Radiometric dating determines the ages of materials and past events by measuring radioactive isotopes and their decay products.

A river is a natural flowing watercourse that drains a landscape, transports sediment, shapes landforms, and supports ecosystems and human activities.

River discharge is the volume of water passing through a river cross-section per unit time, varying with watershed conditions and human activities.

A naturally occurring solid aggregate of minerals or other geological material, recording planetary history and supplying essential resources.

Surface runoff is water flowing over land toward channels or depressions, linking precipitation, drainage, erosion, and pollutant transport.

A tide is the periodic rise and fall of sea level driven principally by the Moon’s and Sun’s gravitational influence on Earth.

The water cycle is the continuous movement and storage of water within and between Earth’s atmosphere, surface, subsurface, and living organisms.