Gizmo Warm-up

Question

Volcanoes, earthquakes, mountains, and other features of Earth’s surface owe their origin to the movements of plates: enormous, slowly-moving sections of Earth’s crust. At plate boundaries, plates collide, move apart, move under or over each other, or slide past one another. The theory of plate tectonics describes how the plates move, interact, and change the physical landscape.

The Plate Tectonics Gizmo shows a cross-section, or side view, of Earth. (Not to scale.) Above the cross section is a bird’s-eye view of the same location.

Turn on Show labels. What are the layers of Earth that you can see?

The lithosphere is a layer of rigid rock that consists of the crust and the upper part of Earth’s mantle. The asthenosphere is a layer of the mantle that can deform like plastic.

Turn on the Boundary name, and click on each boundary. What four boundaries do you see?

Answer 1

In the Plate Tectonics Gizmo, when you turn on the labels, you can typically see the following layers of Earth:

1. Crust - The outermost layer.
2. Lithosphere - The rigid layer that includes the crust and the upper part of the mantle.
3. Asthenosphere - A layer of the mantle below the lithosphere that can deform like plastic.
4. Mantle - The layer beneath the lithosphere, made of semi-solid rock that flows slowly.
5. Outer Core - A liquid layer of molten metal beneath the mantle.
6. Inner Core - The solid innermost layer of Earth.

When you turn on the Boundary name option and click on each boundary, you typically encounter the following four types of plate boundaries:

1. Convergent Boundary - Where two plates collide, often forming mountains or causing subduction.
2. Divergent Boundary - Where two plates move apart, leading to the formation of new crust (e.g., mid-ocean ridges).
3. Transform Boundary - Where two plates slide past one another, leading to seismic activity (e.g., the San Andreas Fault).
4. Subduction Zone - A specific type of convergent boundary where one plate moves under another, leading to geological phenomena such as volcanic activity.

Keep in mind that the specific terms and appearances may vary slightly based on the Gizmo's design, but these are the foundational concepts related to plate tectonics.