Introducing KNOVA — A free reading app with curriculum-aligned passages on History & Science for Grades 3-8Learn More →

Continental Drift Theory — Reading Comprehension

No ratings yet|

Grades

Standards

MS-ESS2-2
MS-ESS2-3

Rate this resource

Send Feedback / Report an Issue

About This Reader

This middle school science passage explores the Continental Drift Theory, focusing on Alfred Wegener's 1912 hypothesis that Earth's continents were once joined as a single landmass called Pangaea and have since moved apart. Students will learn about the scientific evidence Wegener used, including matching fossils, rock formations, and ancient climate clues across continents. The passage also explains why Wegener's ideas were initially rejected and sets the stage for later discoveries in seafloor spreading and plate tectonics. The content aligns with NGSS standards MS-ESS2-2 and MS-ESS2-3, emphasizing scientific reasoning, evidence evaluation, and connections between Earth's systems. Activities include comprehension questions, writing prompts, and graphic organizers, supporting a variety of learners. The resource integrates audio features and is suitable for both classroom and independent study, helping students understand how scientific theories develop over time. Keywords: continental drift, Alfred Wegener, Pangaea, evidence, fossils, plate tectonics, geology.

CONTENT PREVIEW

continental-drift-3 — Evidence of continental drift across continents

Continental drift describes the theory that Earth’s continents have moved slowly across the globe over millions of years. Scientists noticed similarities among the shapes and features of continents on modern maps. For example, the coastlines of South America and Africa appear to fit together like pieces of a puzzle. This observation led geologists to wonder whether the continents were once joined together and later drifted apart.

In 1912, German scientist Alfred Wegener presented the hypothesis of continental drift. He proposed that all continents were part of a single, massive landmass called Pangaea about 250 million years ago. According to Wegener, Pangaea broke apart, and the continents slowly moved to their current positions. Wegener’s idea challenged the common belief that continents and oceans were fixed and unchanging.

Evidence for Continental Drift

Wegener gathered several lines of evidence to support his theory. First, he pointed out the jigsaw-like fit of continents, especially the close match between South America and Africa. Second, he found that identical fossils of ancient plants and animals, such as the reptile Mesosaurus and the plant Glossopteris, were discovered on continents now separated by oceans. This suggested these lands were once connected. Third, Wegener noted that similar rock formations and mountain ranges, like those in eastern North America and western Europe, lined up when the continents were placed together. Finally, he identified glacial deposits—evidence of ancient ice sheets—in present-day tropical regions, showing these areas were once much colder and likely closer to the South Pole.

Challenges and Scientific Debate

Despite strong evidence, many scientists rejected Wegener’s theory at first. The main problem was the lack of a convincing mechanism—how could massive continents move through solid ocean rock? Some proposed that continents plowed through the ocean floor, but this idea did not fit with what was known about Earth's crust. As a result, Wegener’s theory was dismissed by most geologists for decades. However, he persisted, believing that further research would reveal the answer.

Legacy and Connection to Plate Tectonics

Wegener’s work inspired scientists to search for more evidence. In the 1960s, discoveries such as seafloor spreading provided the mechanism that Wegener lacked. Scientists realized that the movement of large sections of Earth's lithosphere, called tectonic plates, could explain continental drift. Today, the theory of plate tectonics is a unifying principle in Earth science, explaining earthquakes, volcanoes, and mountain formation as well as the movement of continents.

Interesting Fact: The Atlantic Ocean is growing wider by about 2.5 centimeters per year as the Americas and Africa/Europe drift apart—about as fast as fingernails grow!

What is the main idea of the continental drift theory?

Continents have moved slowly across Earth's surface over millions of years.Mountains are formed by volcanic eruptions only.Oceans have always been in the same place.Continents are shrinking over time.

Who proposed the hypothesis of continental drift in 1912?

Alfred WegenerCharles DarwinIsaac NewtonMarie Curie

What does the term "Pangaea" mean in the passage?

A supercontinent that included almost all Earth's landmasses.A type of ancient fossil.A mountain range in Europe.A deep ocean trench.

According to the passage, which of the following is NOT evidence used by Wegener?

Similar fossils found on different continents.Matching rock formations across continents.Similar modern animal populations on all continents.Glacial deposits in tropical regions.

In the passage, what does 'mechanism' refer to?

The explanation for how continents could move.A type of ancient plant fossil.A mountain-building process.A kind of ocean current.

Why was Wegener's theory rejected by most scientists at first?

He could not explain how continents moved.He had no evidence at all.Scientists thought Pangaea was still around.He was not a geologist.

Which discovery in the 1960s helped explain how continents move?

Seafloor spreadingPhotosynthesisGlacial meltingMeteor impacts

Which of these statements best describes a cause-and-effect relationship from the passage?

Discovery of identical fossils on separate continents supported the idea that continents were once joined.Oceans contain salt water.Mountains are tall.Some continents have deserts.

True or False: Wegener’s theory is now completely ignored by scientists today.

TrueFalse

True or False: The Atlantic Ocean is currently getting wider each year.

TrueFalse