Physical Geography

Hydrology — the science of water’s occurrence, distribution, and movement on and beneath the Earth’s surface — has developed over several thousand years, moving from practical observation to a rigorous quantitative science.

Early civilizations built their understanding of water around nec...

Alfred Wegener’s hypothesis was continuously rejected by most scientists for 40 years. To prove his theory he persisted to keep on studying Earth’s features, visited libraries, and explored evidence until his death. Wegener never lived to see his theory accepted—he died at the age of 50 while on an expedition in Greenland. Only decades later, in the 1960s, did the idea of con...

Hydrology—the study of water’s movement, distribution, and quality—feeds into a wide range of real-world work. Here’s an overview of the main practical applications:

Hydrology manages water resources by tracking and predicting how water moves through the environment—via precipitation, streamflow, infiltration, evaporation, and groundwater rech...

The global water budget is the accounting of Earth’s total water — roughly 1.386 billion km³ — as it is distributed among reservoirs (oceans, ice caps and glaciers, groundwater, lakes, rivers, atmosphere, and living organisms) and continuously cycled between them through processes like evaporation, transpiration, precipitation, runoff, and in...

The hydrologic cycle (or water cycle) is the continuous natural process by which water moves through Earth’s atmosphere, land, and oceans. It begins with evaporation, where heat from the sun turns liquid water from oceans, rivers, and lakes into water vapor, while transpiration adds moisture from plants. This vapor rises and cools in the atmosphere, undergoing condensation to...