subject
Earth Science
How the planet works as a coupled system: rocks, oceans, atmosphere, and the deep-time processes that shape the surface we live on.
12 lessons in earth science
How a Hurricane Forms
Picture a kettle on a stove. The burner heats the water, the water turns to steam, and the steam rises hard enough to rattle the lid. A hurricane is the same trick on a planetary scale, except the bur…
3 min · foundation
How a River Carves a Canyon
Stand at the edge of a deep canyon and the first thing you notice is the river at the bottom.
3 min · deepening
How Ice Cores Record Past Climates
When snow falls on the high interior of Antarctica or Greenland, it almost never melts.
4 min · deepening
How Ocean Currents Move Heat Around the Planet
If you stand on a beach in western Ireland in January, the air is damp but rarely freezing.
4 min · foundation
How Plate Tectonics Reshapes the Surface
Stand on any continent long enough — geologically speaking — and it will move.
4 min · foundation
Igneous, Sedimentary, Metamorphic: Three Stories Rocks Tell
Pick up a rock from a streambed. It looks like a single object, but it is really a record. The mineral grains inside it were arranged by some specific event — a volcano cooling, a river dropping sand,…
3 min · comparison
Volcanic and Tectonic Mountains: Two Ways the Crust Rises
Stand at the foot of Mount Fuji and then at the foot of the Matterhorn, and you are looking at two mountains that share almost nothing except their height.
4 min · comparison
Why Earthquakes Cluster Along Faults
If you map every earthquake recorded in California over the past century and overlay it on the state's geology, you see something striking: the dots do not scatter evenly.
4 min · deepening
Why It Rains Where It Rains
Stand on the equator at noon and look up. The sun is nearly overhead, the ocean and land below are warm, and the air sitting on that warmth becomes buoyant and begins to rise. As it climbs, it cools. …
4 min · foundation
Why the Carbon Cycle Connects Rocks, Oceans, and Life
A limestone cliff in Dover and a forest in Oregon do not look like parts of the same machine, but they are.
4 min · synthesis
Why the Ocean Is Salty
If you have ever swallowed a mouthful of seawater at the beach, you know the ocean tastes nothing like a glass of water from the tap.
3 min · foundation
Why the Sky Is Blue
Stand outside at noon on a clear day and look straight up. The Sun is white, but the sky around it is blue. That is strange, if you stop to think about it. The light coming from the Sun is the same li…
3 min · foundation