Rock Transformations: Review

Sophia is learning about rocks in her geology class. How does an igneous rock form?

• When sediment is compacted and cemented together

• When magma cools

• Through extreme heat and pressure

Answer explanation

Igneous rocks form when magma cools and solidifies, either beneath the Earth's surface or after erupting as lava. This process distinguishes them from sedimentary rocks, which form from compacted sediments, and metamorphic rocks, which form under heat and pressure.

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NGSS.MS-ESS2-1

Olivia and Liam are studying rocks in their geology class. How does a sedimentary rock form?

• When sediment is compacted and cemented together

• When magma cools

• Through extreme heat and pressure

Answer explanation

Sedimentary rocks form when layers of sediment are compacted and cemented together over time, making the correct choice. The other options describe processes for igneous and metamorphic rocks.

Abigail and Daniel are building a sandcastle at the beach. What is cementation in this context?

• the process of sediment being buried and pressed together

• the process of sediment being glued together

• hot liquid rock cooling

Answer explanation

Cementation is the process where sediment particles are glued together by minerals precipitating from water, forming solid rock. This distinguishes it from mere burial and pressing, which is compaction.

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NGSS.MS-ESS2-2

Elijah and Zoe are building a sandcastle at the beach. What is compaction in this context?

• The process of sediment being buried and pressed together

• The process of sediment being glued together

• The process of magma cooling

Answer explanation

Compaction is the process where sediment is buried under additional layers and subjected to pressure, causing the particles to be pressed together, which is accurately described by the correct choice.

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NGSS.MS-ESS2-2

What is erosion?

• the process of sediment being buried and pressed together

• the process of rock breaking down into smaller pieces due to wind or moving water

• The movement of sediment from one place to another, often caused by wind or flowing water

Answer explanation

Erosion is specifically the movement of sediment from one location to another, primarily driven by natural forces like wind and flowing water, distinguishing it from processes like sedimentation or weathering.

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NGSS.MS-ESS2-2

What is weathering?

• the process of rock breaking down into smaller pieces due to wind or moving water

• the process by which rock material moves under Earth's outer layer and into the mantle due to plate motion

• the movement of sediment from one place to another, often caused by wind or flowing water

Answer explanation

Weathering is the process of rock breaking down into smaller pieces due to wind or moving water. This distinguishes it from erosion, which involves the movement of sediment, and plate motion, which refers to tectonic activity.

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NGSS.MS-ESS2-2

What is magma?

• the ability to make things move or change

• small pieces of rock

• hot liquid rock below the surface of Earth

Answer explanation

Magma is defined as hot liquid rock located beneath the Earth's surface. This distinguishes it from other options, such as small pieces of rock or the ability to make things move, which do not accurately describe magma.

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NGSS.MS-ESS2-2

What is sediment?

• small pieces of rock

• one of the very large sections of hard, solid rock that make up Earth's outer layer

• one of the many different types of matter that make up rocks

Answer explanation

Sediment refers to small pieces of rock that have been broken down through weathering and erosion. This makes 'small pieces of rock' the correct choice, as it directly defines what sediment is.

A rock with large mineral grains in it would probably be an __________ rock.

Answer explanation

A rock with large mineral grains is typically an igneous rock, as these rocks form from the cooling and solidification of magma, allowing large crystals to develop. Other rock types, like sedimentary or metamorphic, usually have finer grains.

The interlocking crystals of igneous rock help to classify it since these crystals are evidence of how the rock formed. The crystals are a result of–

• sediments being deposited.

•  particles forming layers.

• chemical reactions of minerals.

• melted rock that cooled.

Answer explanation

The interlocking crystals in igneous rock form from melted rock that cooled. This process indicates the rock's formation, distinguishing it from sedimentary or metamorphic rocks.

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NGSS.MS-ESS2-2