Exploring Earth's Layers Quiz

Defining Characteristics of Earth

• One of Earth's defining characteristics is its layered structure.

Human Experience of Earth's Movements

• Humans mostly experience Earth's movements through the changing seasons and daylight hours.

Layers of the Earth

• Earth has layers due to density and pressure differences.
• The two types of crust on Earth are continental and oceanic crust.
• Continental crust is composed of granite and sedimentary rocks.

Earth's Perspective from Space

• From space, Earth appears as a blue and white planet.

Earth's Layers and Boundaries

• The boundary between the crust and upper mantle is called the Mohorovičić discontinuity (Moho).
• The outer core is the liquid layer of the Earth.
• Temperature and pressure increase with depth in the Earth's layers.
• At a depth of 1500 km, the interior temperature of the Earth is approximately 3000°C.
• At a depth of 2000 km, the interior pressure of Earth is approximately 145 GPa.
• The boundary between the outer core and inner core is located at a depth of approximately 5150 km.

Density, Pressure, and Temperature Relationships

• Density, pressure, and temperature are related in the Earth's layers, with density increasing with pressure and temperature.

Scientific Investigation of Earth's Layers

• Scientists know about the different layers of Earth through seismic data and other indirect methods, as they have never been below the crust.

Earth's Interior Properties

• At a depth of 2500 km, the interior rock density of the Earth is approximately 4 g/cm³.
• A task requiring finding the interior temperature, pressure, and rock density at various depths is seismic tomography.

Geologic Time

• The four major divisions of geologic time are Eons, Eras, Periods, and Epochs.
• The Precambrian Eon constitutes approximately 90% of Earth's history.
• The largest division of geologic time is measured in Eons.
• The theory that explains how the Earth formed is the Nebular Hypothesis.
• There are four major Eons: Hadean, Archean, Proterozoic, and Phanerozoic.
• The Phanerozoic Eon is broken into Paleozoic, Mesozoic, and Cenozoic Eras.

Earth's Early Atmosphere and Life

• The first atmosphere was composed of gases released during outgassing, including methane, ammonia, and water vapor.
• The earliest flowering plants appeared during the Cretaceous Period.
• The Phanerozoic Eon is broken up into three Eras: Paleozoic, Mesozoic, and Cenozoic.
• The distribution of fossils indicates the movement of continents over time.
• Knowing the position of continents over time is significant for understanding Earth's history.

Evolution of Life

• Cyanobacteria evolved 3.8 billion years ago and contributed to adding oxygen to the oceans.
• The Phanerozoic Eon accounts for only 10% of Earth's history.
• The Eras in the Phanerozoic Eon are Paleozoic, Mesozoic, and Cenozoic.
• Time during the Phanerozoic Eon is broken up into smaller units: Eras, Periods, and Epochs.
• Each Era is divided into Periods, which are further divided into Epochs.