Physical Geography

 Geology the science that deals with the earth's physical structure and substance, its history, and the processes that act on it.

---

1. Plate tectonics

The super-continent Pangaea, with its connected South America and Africa, broke apart 200 million years ago. But the continents haven't stopped shifting -- the tectonic plates beneath our feet (in Earth's two top layers, the lithosphere and the asthenosphere are still traveling at about the rate your fingernails grow. Michael Molina discusses the catalysts and consequences of continental drift.

---

---

2. Layers of the Earth

The Earth is approximately 4,000 miles from the center to its surface, but what makes up those miles of earth? Let's take a journey inside with M.I.T's Researchers.