Chapter#1

How long did it take Earth's oceans to form?

500 million years

What is a scientific theory?

A well-substantiated explanation that is supported by facts, tested hypotheses, and logical inferences

What is the basis for relative positions of Earth's physical layers?

Material density, with the least-dense material on the surface and the most-dense material in the center

Which of the following is the first step of the scientific method?

Observation

Which of the following has the deepest waters?

Pacific Ocean

Which of the following is the largest natural geographic feature on Earth?

Pacific Ocean

What triggers outgassing to occur?

Rising of low-density gases to the surface

Imagine that you are enjoying a day at the beach in California, exploring tide pools. You find a California sea hare in the shallow water and gently scoop it into your hand. As you touch it, the sea hare releases purple ink into your hand. You think maybe the sea hare released the ink to scare you (a potential predator) away, but you are not sure. What is the next step you would need to take to advance your understanding to the next level of scientific inquiry?

Testing

What must be true about early Earth in order for water to have accumulated on its surface?

There were depressions in the crust.

How did Earth's early oceans form?

Water vapor was expelled into the atmosphere by volcanic eruptions, which condensed to form rain that was then collected on Earth's surface.

What element(s) are found in high concentrations in continental crust?

• Aluminum • Silica

Which statement(s) below correctly describe differences between oceanic and continental crust?

• Continental crust is thicker than oceanic crust. • Continental crust floats higher on the mantle than oceanic crust. • Continental crust is mainly composed of granite, whereas oceanic crust is mainly composed of basalt.

Rocks in which layer(s) of Earth are rigid?

• Lithosphere • Inner core • Mesophere

What element(s) are found in high concentrations in oceanic crust?

• Magnesium • Iron

Imagine that you are enjoying a day at the beach in California, exploring tide pools. You find a California sea hare in the shallow water and gently scoop it into your hand. As you touch it, the sea hare releases purple ink into your hand. You think maybe the sea hare released the ink to scare you (a potential predator) away, but you are not sure. What steps of the scientific method have you performed in your inquiry?

• Observation • Hypothesis formulation

Waters from which ocean basins combine to form the Southern Ocean?

• Pacific • Atlantic • Indian

Which of the following statements is/are true regarding Earth's oceans?

• The Southern Ocean is one of the least-studied areas on planet Earth. • NASA satellites fly over Antarctica. • Earth's ocean is one big interconnected body of water.

Which of the following statements is/are true regarding Earth's core?

• The core is composed of mainly iron and nickel, with some sulfur. • Earth's core is composed of two layers that differ in physical properties. • The outer core is liquid because it is so hot.

Which of the following statements is/are true regarding the scientific method?

• The scientific method involves repeated testing and adjustment of hypotheses to explain observations. • Scientists make predictions based on established theories. • The scientific method is an ongoing cycle.

Which ocean basin is currently covered by extensive sea ice for much of the year?

Arctic

Why do scientists think that comets from the Kuiper belt may have contributed to Earth's early oceans?

Comets in the Kuiper belt have a molecular signature similar to the water on Earth.