Floods and Volcanoes Leave Rock Clues — Reading Comprehension

Earth is always changing, and some of these changes happen because of floods and volcanoes. These natural events may seem destructive, but they also leave behind important clues in rocks.

A flood happens when water covers land that is usually dry, often because of heavy rain or melting snow. Floods can move large amounts of soil, sand, and rocks from one place to another. This process is called erosion. As water flows quickly, it picks up pieces of rock and carries them downstream. When the water slows down, it drops these materials. The dropped pieces are called sediment. Over time, layers of sediment can build up and form new types of rocks, called sedimentary rocks. Scientists can study these layers to learn about floods that happened long ago.

Volcanoes are mountains that can erupt, sending out lava, ash, and gases. When lava cools and hardens, it forms rocks called igneous rocks. These rocks often look different from sedimentary rocks because they are made from melted rock. Some volcanoes erupt quickly, and others erupt slowly, but both leave behind rock clues that scientists can study. For example, the black rocks found in Hawaii were formed by cooled lava from volcanoes.

By looking at the kinds of rocks in an area, scientists can figure out if there were floods or volcanoes there in the past. They use these rock clues to understand how Earth’s surface has changed over time.

Interesting Fact: The fossils of plants and animals are sometimes trapped inside sedimentary rocks, helping scientists learn about life from millions of years ago!

What forms when lava cools?

What does erosion do?

What is sediment made of?

How do scientists learn about old floods?

Why are fossils important in rocks?

If a volcano erupts, what forms?

Floods never move rocks. True or false?

What is 'erosion'?