Text reads: "The Mysteries of Life with Tim and Moby."
A boy, Tim, reads from a typed letter.
TIM: Dear Tim and Moby. What in the world is a "Pangaea"? Signed, DAN (via the Internet)
Tim, and his robot friend Moby, are standing in a desert.
TIM: Sounds like we need to get into the theory of plate tectonics!
TIM: If you look at the shapes of Earth's continents, Africa and South America look like pieces of a puzzle that could snap together.
An animated map shows the Earth's continents. The continents Africa and South Americas pop up and press each other.
TIM: This supports the theory that all of continents were once one big continent called Pangaea. Scientists believe Pangaea existed about 2 or 300 million years ago, then it started to break apart, eventually forming the continents we know today.
An image shows a world map with a single, huge continent. Then it shows Pangaea breaking into several pieces which drift apart from one another. The continents assume the shapes we know today.
TIM: Now, it's not like they were floating, the ocean floor was moving too! The outer layer of the Earth, or crust, is broken up into about a dozen major, and many minor, tectonic plates. These plates float around on a layer of molden rock called the outer mantle.
An image shows a picture of the Earth, then it shows the inside layers of the Earth. The outside layer is labled "crust" and the layer under it is labled "mantle."
TIM: When the plates move, continents shift along with them in a process called continental drift. This motion explains why fossils of the same kinds of prehistoric animals were found on the northeast coast of South America and the southwest coast of Africa.
Fossil pictures are placed on northeastern South America and southwestern Africa.
TIM: Well, when the continental plates shift, you hardly ever notice the gound moving; continents only move about a few centimeters every year!
Tim puts his head against the ground, trying the notice the ground moving.
TIM: Oh yeah, I'm getting to that. Lots of things happen at those active boundaries between plates. Volcanoes, earthquakes, mountains, and trenches are all results of movement along plate boundaries.
An image shows plate boundaries. Images of a volcano, earthquake, mountain, and trench appear on the screen, too.
TIM: Divergent boundaries are where plates are moving apart, and new crust is created by liquid rock pussing up from the mantle.
An animation shows divergent boundaries and the activities Tim describes.
TIM: Convergent boundaries are where plates are moving toward each other and sometimes one plate sinks, or is subducted, under another.
An animation shows convergent boundaries and the activities Tim describes.
TIM: Transform boundaries are where plates slide horizontaly pass each other and cause friction.
An animation shows transform boundaries and the activities Tim describes.
TIM: These plates are always moving, slowly changing the face of the Earth. Who knows what the world could look like in another, couple of, hundred million years!
Moby is shown holding a globe.
Moby shows a piece of land that looks like his head.
TIM: Oh yeah, sure Moby.
TIM: Well, it's not impossible, but it's unlikely.
MOBY: Beep! Beep! Beep!
TIM: You're insane.