Seafloor Spreading and Plate Tectonics Unveiled

The video explores seafloor spreading, a key concept in plate tectonics, starting with Alfred Wegner's continental drift theory. It discusses the development of ocean floor mapping using sonar, revealing geological features like mid-ocean ridges. The video presents four key pieces of evidence for seafloor spreading: ocean floor fractures, increasing rock age away from ridges, sediment thickness, and magnetic patterns. These findings confirm the theory of plate tectonics.

What was Alfred Wegener's revolutionary idea about continents?

• Continents are shrinking over time.

• Continents are stationary and unchanging.

• Continents are slowly moving slabs of rock.

• Continents are floating on water.

What technology did scientists use in the 1950s to map the ocean floor accurately?

• Infrared scanning

• Satellite imaging

• Sonar

• Radar

What geological feature was discovered running down the Atlantic Ocean basin?

• A large plateau

• A vast desert

• A deep canyon

• A massive mountain range

What happens at a seafloor spreading center?

• Plates collide and form mountains.

• Magma rises and pushes plates apart.

• Plates sink into the mantle.

• Plates slide past each other.

How does the age of seafloor rocks change as you move away from the mid-ocean ridge?

• The rocks disappear.

• The rocks get older.

• The rocks remain the same age.

• The rocks get younger.

What does the thickness of ocean floor sediments indicate?

• The age of the ocean floor

• The temperature of the ocean

• The salinity of the water

• The speed of ocean currents

What was the purpose of studying magnetism during World War II?

• To measure ocean temperatures

• To identify sea mines and submarines

• To map ocean currents

• To detect enemy aircraft

What phenomenon is recorded in the solidified rocks on either side of a mid-ocean ridge?

• Tsunamis

• Volcanic eruptions

• Magnetic reversals

• Earthquakes

What causes the Earth's magnetic field?

• The gravitational pull of the moon

• The movement of molten metals in the outer core

• The alignment of the planets

• The rotation of the Earth

What is the significance of matching patterns of seafloor magnetism on either side of a ridge?

• It indicates the location of oil reserves.

• It proves the existence of underwater volcanoes.

• It confirms the theory of seafloor spreading.

• It shows the presence of ancient civilizations.