Earth Changes Over Millions of Years — Reading Comprehension

Earth has not always looked the way it does today. Over millions of years, many powerful forces have changed the surface of our planet. These changes are caused by both slow and fast processes.

One slow process is weathering. Weathering happens when rocks break down into smaller pieces from wind, water, or ice. Over time, weathering can turn huge rocks into sand and soil. Another slow process is erosion. Erosion is when wind, water, or ice move rocks and soil from one place to another. For example, a river can carry away soil and carve deep valleys called canyons.

Some changes happen quickly. Earthquakes can crack the ground and move large sections of land in seconds. Volcanoes can erupt and create new land by pouring out lava that hardens into rock. These fast events change the Earth’s surface right away.

Earth’s outer shell is made of large pieces called tectonic plates. These plates move very slowly, but when they push against each other, they can form mountains. The Himalayas, the tallest mountains in the world, were made when two plates collided.

We can learn about Earth’s past by studying fossils. Fossils are the remains or signs of ancient plants and animals found in rocks. They show us that Earth’s surface and life have changed over time. For example, scientists have found fish fossils on mountains, which means those mountains were once underwater!

Interesting Fact: The Grand Canyon was formed over millions of years by the Colorado River slowly eroding rock and soil away, creating the giant canyon we see today.

What breaks down rocks into smaller pieces?

What forms when a river erodes land?

What is the result of volcanic eruptions?

How do mountains form?

What can we learn from fossils?

What happens during an earthquake?

Weathering is a fast process. True or false?

What are tectonic plates?