Earth's Structure: Lithosphere, Asthenosphere, Crust

• Earth's structure comprises compositional and mechanical layers.

Lithosphere

• The lithosphere is the Earth's rigid outermost shell.
• It includes the crust and the uppermost part of the mantle.

Asthenosphere

• The asthenosphere is a highly viscous, mechanically weak and ductile region of the upper mantle.
• It lies just below the lithosphere.
• The asthenosphere allows for the movement of the lithosphere.

Crust

• The crust is the outermost solid layer of the Earth.
• It is chemically distinct from the underlying mantle.
• There are two types of crust: oceanic and continental.
• Oceanic crust is thinner (around 5-10 km) and denser (about 3.0 g/cm³) than continental crust.
• Continental crust is thicker (around 30-50 km) and less dense (about 2.7 g/cm³).

Mantle

• The mantle is the largest layer of the Earth in terms of volume.
• It is located beneath the crust and above the core.
• The mantle is primarily composed of silicate rocks rich in iron and magnesium.
• It is divided into the upper and lower mantle based on changes in mineral composition and physical properties.

Core

• The core is the innermost layer of the Earth.
• It is primarily composed of iron and nickel.
• The core is divided into two parts: the liquid outer core and the solid inner core.
• The outer core is responsible for generating the Earth's magnetic field through the movement of liquid iron.
• The inner core is solid due to immense pressure.

Investigating Rock Density

• Representative rock samples from the crust, mantle, and core have different densities.
• A practical investigation can be conducted to compare the density differences between these rock samples.
• Density is calculated by dividing mass by volume.

Scientific Investigations

• Inquiry questions and hypotheses are developed to identify a concept that can be investigated scientifically.
• Investigations involve primary and secondary data.
• Variables and experimental controls are used to ensure a valid procedure for reliable data collection.
• Appropriate technologies are used to ensure and evaluate accuracy.
• Quantitative processes are applied where appropriate.
• Error, uncertainty, and limitations in data are assessed.

Data Analysis

• Trends, patterns, and relationships in data and information are derived.
• The relevance, accuracy, validity, and reliability of primary and secondary data are assessed.

Communication

• Suitable forms of digital, visual, written, and/or oral communication are selected and used.
• Appropriate scientific notations, nomenclature, and scientific language are applied to communicate in a variety of contexts.