Density
BrainPop: Measuring Matter

Earth's Structure
BrainPop: Earth's Structure
Greatest Discoveries with Bill Nye - The Core of the Earth

Continental Drift and Plate Tectonics
BrainPop: Plate Tectonics
Greatest Discoveries with Bill Nye - Continental Drift
USGS: Plate Tectonics in a Nutshell
USGS: This Dynamic Earth: The Story of Plate Tectonics

Seafloor Spreading
Greatest Discoveries with Bill Nye - Seafloor Spreading
NOAA Ocean Explorer: Mid-Ocean Ridges
BrainPop: Ocean Floor

Earthquakes and Volcanoes
BrainPop: Earthquakes
BrainPop: Volcanoes
Interactive Map of Recent Volcanoes and Earthquakes World-Wide
Kilauea: Mountain of Fire
National Geographic: Volcanoes 101
National Geographic: Earthquakes 101
Hawaii: It came from the sea
How the Earth was Made: How was Hawaii Formed?
USGS: U.S. Volcanoes List
Columbia University: Subduction Zones