The Earth rotates on its axis from west to east. This rotational direction is why the Sun, Moon, and stars appear to rise in the east and set in the west. This motion is fundamental to the cycle of day and night and the Coriolis effect, which influences global wind and ocean current patterns.
142
Approximately what percentage of the Earth's total land surface is occupied by plateaus?
Plateaus, often referred to as tablelands, are elevated flat-topped landforms. Geographers estimate that plateaus cover roughly 45% of the Earth's total land surface area. These features are found on every continent and vary significantly in elevation, from low-lying plateaus to high-altitude regions like the Tibetan Plateau, playing a crucial role in global topography.
143
Which type of tectonic plate is primarily composed of older, less dense rocks?
Continental plates are composed primarily of granitic rocks, which are generally older and less dense than the basaltic rocks that make up oceanic plates. Because of their lower density, continental plates are more buoyant and do not subduct easily during tectonic collisions, allowing them to persist over geological timescales.
144
Which of the following components are considered major sub-disciplines within the study of physical geography?
Physical geography is a broad field that integrates various natural sciences. It encompasses the study of soils (pedology), vegetation (biogeography), atmospheric conditions (climatology and meteorology), and landforms (geomorphology). Therefore, all the listed options are essential components of the physical geography curriculum.
145
Which layer of the Earth is situated between the crust and the core?
The Earth is composed of three primary layers: the crust (outermost), the mantle (middle), and the core (innermost). The mantle is the thickest layer, extending from the base of the crust to the outer core, and is primarily composed of silicate rocks that exhibit plastic behavior over geological timescales.
146
Which planet is recognized as the eighth and outermost major planet in our solar system?
In our solar system, the planets are ordered by their distance from the Sun. Starting from the center, they are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and finally Neptune, which is the eighth planet.
147
What is the approximate thickness of the Earth's outer core?
The Earth's outer core is a liquid layer composed of iron and nickel. While scientific estimates for its thickness vary, the provided answer is 1,250 km. Note: Modern geophysical data often suggests a thickness closer to 2,200-2,300 km.
148
What is the approximate thickness of the Earth's mantle layer?
The Earth's mantle is the thick layer located between the crust and the outer core. It extends from the Mohorovičić discontinuity at the base of the crust to a depth of approximately 2,900 kilometers, where it meets the outer core. This region makes up the majority of the Earth's volume.
149
What term describes large landforms that rise steeply above their surrounding terrain?
Mountains are significant landforms that extend above the surrounding land in a limited area, usually in the form of a peak. They are formed through various tectonic processes, including volcanic activity and crustal deformation. Unlike folding, which is a process, or Pangea, which is a historical supercontinent, a mountain is the physical landform resulting from such geological forces.
150
What is the approximate average temperature of the Earth's mantle?
The temperature of the mantle varies significantly with depth. While the upper mantle starts at lower temperatures near the crust-mantle boundary, it increases with depth. 1200°C is often cited as a representative average temperature for the upper mantle, particularly near the asthenosphere where partial melting occurs.
