Our Changing Earth Online Quiz

Magma is molten rock located beneath the Earth's surface. Once it erupts onto the surface, it is called lava.

Magma typically collects in a magma chamber, travels up through a conduit or channel, and exits through the vent of the volcano.

Earthquakes occur most frequently at the boundaries where tectonic plates meet, as the movement and friction between these plates release energy.

The crust is solid, and the inner core is solid due to extreme pressure. The mantle is semi-solid (plastic), and the outer core is liquid.

The mantle is the thickest layer of the Earth, making up the majority of the Earth's volume.

Subduction occurs when one tectonic plate moves under another, forcing it into the mantle where it melts and can lead to volcanic activity.

The San Andreas Fault is a classic example of a transform plate boundary, where two tectonic plates slide horizontally past each other. Convergent boundaries involve collision, while divergent boundaries involve separation.

Fossil evidence across oceans suggests that continents were once joined together, supporting the theory of continental drift. This indicates that landmasses have moved over geological time.

Divergent boundaries occur where tectonic plates move away from each other. This movement often allows magma to rise and create new crust.

Convergent boundaries occur where two tectonic plates move toward each other and collide. This process can lead to mountain building or subduction zones.

The outer core is composed primarily of liquid iron and nickel. The inner core is solid due to extreme pressure, while the mantle is semi-solid rock.

Earth's outer core is composed of liquid iron and nickel, which generates Earth's magnetic field through convective motion. The inner core is solid, while the mantle and crust are solid or plastic rock.

The lithosphere, which includes the crust and the uppermost part of the mantle, is broken into tectonic plates. The crust is the outermost layer.

A seismograph is an instrument used to detect and record seismic waves caused by earthquakes. A seismogram is the actual record produced by the machine.

Continental drift is the hypothesis that Earth's continents have moved over geological time relative to each other. Plate tectonics is the broader theory explaining how they move.

Divergent boundaries allow magma to rise from the mantle to fill the gap created by separating plates, cooling to form new oceanic crust.

Alfred Wegener proposed the hypothesis of continental drift in the early 20th century. He gathered evidence from fossils, rock formations, and climate data.

Pangaea is the name of the supercontinent that existed approximately 335 to 175 million years ago, containing most of Earth's landmasses.

Mid-ocean ridges are underwater mountain systems formed by plate tectonics at divergent boundaries, where seafloor spreading occurs.