How Basalt Rock Forms — Reading Comprehension

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This educational module, aligned with NGSS MS-ESS2-2, delves into the fascinating process of how basalt rock forms. Students will read an engaging, audio-integrated passage that explains the role of volcanic activity, magma, and lava in creating this common igneous rock. Key terms like 'volcano,' 'magma chamber,' 'eruption,' 'cooling,' and 'minerals' are defined in simple language suitable for a Grade 6 reading level. The module includes comprehension questions, a glossary, and short answer questions to reinforce understanding of how geoscience processes change Earth's surface. It's an excellent resource for exploring rock formation and the dynamic nature of our planet.

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Basalt rock forms from lava cooling after a volcanic eruption on land and ocean floor. 📝 Image caption: Basalt forms when lava cools quickly after erupting from a volcano onto land or sea. — Basalt forms when lava cools quickly after erupting from a volcano onto land or sea.

Have you ever wondered how some of the most common rocks on Earth are made? Let's explore how basalt rock forms, a fascinating process that helps us understand how our planet's surface changes over time. Basalt is a type of igneous rock, which means it forms from the cooling and hardening of molten material.

The journey of basalt begins deep inside Earth, where intense heat melts solid rock into a thick, hot liquid called magma. This magma often gathers in large underground spaces known as magma chambers. Think of these chambers as giant storage tanks for molten rock. When pressure builds up in these chambers, the magma can force its way through cracks in the Earth's crust.

If magma reaches the Earth's surface, it becomes lava. This usually happens during a volcanic eruption. When lava flows out of a volcano, it is incredibly hot, often reaching temperatures over 1,000 degrees Celsius (1,800 degrees Fahrenheit)! As this lava spreads across the land or ocean floor, it begins to cool down very quickly when it touches the cooler air or water.

This rapid cooling is key to how basalt forms. When lava cools quickly, the tiny minerals inside it don't have much time to grow large. Instead, they form very small crystals, making basalt a fine-grained rock. If you look closely at a piece of basalt, you might see these tiny crystals, but they are often too small to see without a magnifying glass. Basalt is typically dark gray or black in color and is one of the most common rocks found on Earth's ocean floors and in many volcanic regions.

Basalt formation is a crucial part of geoscience processes that have shaped Earth's surface for billions of years. It's a clear example of how molten material from deep within our planet can create new landforms and change landscapes dramatically through volcanic activity.

Interesting Fact: The Moon's dark areas, called maria (Latin for 'seas'), are actually vast plains of basalt rock formed from ancient volcanic eruptions!

What is magma?

Solid rock undergroundMolten rock undergroundRock on Earth's surfaceCooled volcanic rock

What color is basalt typically?

Light grayDark gray or blackRed or orangeWhite or clear

How does basalt rock typically form?

Slow cooling of magmaQuick cooling of lavaWeathering of other rocksPressure on sediments

Why do minerals in basalt form small crystals?

Not enough mineralsSlow cooling occursLava cools rapidlyMagma stays underground

Where is basalt commonly found on Earth?

Mountain peaksDesert sandsOcean floorsDeep in forests

What is the molten material called once it reaches Earth's surface?

MagmaBasaltLavaMineral