Learning about the Theory of Continental Drift

Jun 14, 2021

2 min read

An Overview of the Theory of Continental Drift

The theory of continental drift argues that Earth’s continents are moving. It claims that the continents were once joined together in a massive supercontinent called Pangaea. The supercontinent broke apart as the continents drifted away from each other.

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Alfred Wegener

Alfred Wegener proposed his continental drift theory in 1912 based on four observations he made about the continents. First, he saw fossils of the same plants and animals in both South America and Africa. Other scientists believed these fossils resulted from ancient land bridges that used to connect the continents, but Wegener disagreed. Second, the rock formations along the coasts of different continents were similar. For example, the Appalachians in North America and the Caledonians in Scotland looked like one continuous mountain chain separated by the Atlantic Ocean. Third, Wegener found tropical plant fossils within the Arctic Circle in Norway. He concluded that they were most likely there because Norway used to be located closer to the equator where tropical plants grow. Finally, Wegener noticed that the continents’ shapes looked like they could fit together like puzzle pieces.

The Response to the Theory of Continental Drift

Scientists at the time laughed at Wegener’s theory. They said he had no business talking about geology when he wasn’t a geologist. Instead, Wegener was a meteorologist, climatologist, and geophysicist. He had started working on his revolutionary theory after browsing for pleasure in his university’s library.

Other scientists were also skeptical of the continental drift theory because Wegener could not explain how the continents moved. After an initial uproar, scientists largely forgot the theory of continental drift until the 1960s. In the 1960s, geologists introduced the theory of plate tectonics. The theory argued that the Earth’s solid outer layer, called the lithosphere, was made up of giant plates that floated on a softer layer called the asthenosphere. The tectonic plates moved because convection currents within the mantle pushed them. The mechanism behind continental drift was discovered. Alfred Wegener was right; the continents were moving.

Resources for Teachers

Do you want to share this information on continental drift with your science students? You can give them this reading passage and comprehension question set! I also include a list of related videos to help students build background knowledge around the theory of continental drift.