Geological Discoveries During World War II

During WWII, Harry Hess, a geology professor and Navy reservist, used sonar to discover mountains on the Pacific Ocean floor. This led to the discovery of the Mid-Atlantic Ridge, a massive underwater mountain range. Hess proposed the theory of seafloor spreading, suggesting that new crust forms at ocean ridges and is recycled back into the Earth through subduction. This process is a key part of plate tectonics, explaining how the Earth's surface is constantly reshaped.

What role did Harry Hess play during World War II?

• He was a diplomat negotiating peace treaties.

• He was a Navy reservist and a geology professor.

• He was a pilot in the Air Force.

• He was a scientist developing nuclear weapons.

What did Harry Hess discover about the ocean floor?

• It was completely flat and covered with sediment.

• It was covered with ice.

• It had mountains, canyons, and trenches.

• It was made entirely of coral reefs.

What significant geological feature was discovered in the Atlantic Ocean in 1953?

• The Mid-Atlantic Ridge

• The Mariana Trench

• The Bermuda Triangle

• The Great Barrier Reef

How high does the Mid-Atlantic Ridge rise above the surrounding seafloor?

• About 500 meters

• About 1 kilometer

• About 4 kilometers

• About 2.5 kilometers

What did Harry Hess conclude about the age of the Atlantic ocean floor?

• It was progressively older the further it moved from the ridge.

• It was younger near the continents.

• It was older near the Mid-Atlantic Ridge.

• It was the same age throughout.

What is the process called where new crust is formed at the ocean ridges?

• Plate tectonics

• Continental drift

• Seafloor spreading

• Subduction

What happens to the Earth's crust in the process of subduction?

• It floats on the ocean surface.

• It remains unchanged.

• It is recycled back into the Earth's interior.

• It is formed anew at the ocean ridges.

Why doesn't the Earth grow larger despite new crust being formed?

• The new crust is very thin.

• New crust is consumed in other areas.

• The Earth's size is fixed by gravity.

• The Earth is constantly shrinking.

What is the term for the recycling of the ocean floor back into the Earth?

• Erosion

• Sedimentation

• Volcanism

• Subduction

What is the most powerful force on the face of the Earth according to the video?

• Plate tectonics

• Gravity

• Seafloor spreading

• Subduction