Earth's Elevation and Plate Tectonics

Emily from MinuteEarth explains Earth's elevation distribution, which differs from Venus's normal distribution. Earth's surface has a double-humped elevation curve due to the density differences between oceanic and continental crusts. These differences lead to unique geological features like mountain ranges when tectonic plates collide. If Earth had a normal distribution like Venus, only a small portion would be above sea level, highlighting the uniqueness of Earth's topography.

What is the total range of elevations on Earth from the highest to the lowest point?

• 80,000 feet

• 70,000 feet

• 65,000 feet

• 50,000 feet

How does the elevation distribution of Venus differ from that of Earth?

• Venus has a single peak distribution.

• Venus has no elevation distribution.

• Venus has more extreme elevations than Earth.

• Venus has a double-humped distribution like Earth.

What is the primary reason for Earth's double-humped elevation distribution?

• The presence of mountains.

• The presence of large oceans.

• The density difference between oceanic and continental crust.

• The Earth's rotation.

What happens when two oceanic plates collide?

• They create a volcanic island.

• They form a new ocean.

• The denser plate sinks back into the Earth.

• They both rise to form mountains.

Why is the continental crust thicker than the oceanic crust?

• Because it is made of denser material.

• Because it is less dense and rises higher.

• Because it is constantly eroded.

• Because it is older.

What is the average thickness of the continental crust compared to the oceanic crust?

• Twice as thick

• Three times as thick

• Four times as thick

• Five times as thick

What is the main consequence of the density difference between oceanic and continental plates?

• Oceanic plates float on top of continental plates.

• Continental plates sink into the mantle.

• Oceanic plates sink when they collide with continental plates.

• Continental plates are denser than oceanic plates.

What is the result when two continental plates collide?

• They form a trench.

• One plate sinks beneath the other.

• They create a new ocean.

• They both rise to form mountains.

What would Earth's surface look like if it had a normal distribution like Venus?

• All of the surface would be below sea level.

• Most of the surface would be above sea level.

• There would be no land above sea level.

• Only about 5% would be above sea level.

Why should we be glad that Earth's elevation distribution is not normal?

• It allows for more land above sea level.

• It creates more extreme weather.

• It results in more earthquakes.

• It leads to more volcanic activity.