Grade 7 Earth Science Unit One

Questions and Answers

What are the three main layers of the Earth?

Crust, mantle, core (correct)

Crust, mantle, outer core

Crust, lithosphere, inner core

Crust, hydrosphere, atmosphere

Which type of rock is formed from cooled and solidified magma?

Metamorphic rock

Volcanic rock

Igneous rock (correct)

Sedimentary rock

What is the primary component of the Earth's core?

Aluminum and silicon

Copper and zinc

Iron and nickel (correct)

Calcium and magnesium

Which type of rock is commonly formed from sediment deposition?

Sedimentary rock Signup and view all the answers

What defines minerals in the Earth's crust?

Naturally occurring inorganic solids with a specific structure Signup and view all the answers

Which layer of the Earth lies directly beneath the crust?

Mantle Signup and view all the answers

Which of the following is NOT a source of nutrients from rocks?

Weight-loss supplements Signup and view all the answers

What is the primary state of the elements in the outer layer of the Earth?

Solid Signup and view all the answers

Which element is the most abundant in the Earth's crust, based on weight percentage?

Oxygen Signup and view all the answers

What is a common characteristic of igneous rocks?

Formed from the cooling and solidification of molten rock Signup and view all the answers

Which of the following elements accounts for approximately 5% of the Earth's crust?

Iron Signup and view all the answers

What type of materials make up the Earth's crust?

Rocks Signup and view all the answers

What is the average thickness range of continental crust?

30 to 40 km Signup and view all the answers

Which of these elements has the lowest abundance in the Earth's crust?

Others Signup and view all the answers

Which elements primarily compose the oceanic crust?

Silicon (Si) and Magnesium (Mg) Signup and view all the answers

What is the approximate thickness of the Earth's mantle?

2,900 km Signup and view all the answers

What are the rock-forming minerals characterized as?

Inorganic solids Signup and view all the answers

Which of the following describes the state of the outer core?

Liquid or semi-liquid Signup and view all the answers

Which element is found in the Earth's crust at approximately 2.83%?

Sodium Signup and view all the answers

What is the main component of the inner core?

Nickel (Ni) and Iron (Fe) Signup and view all the answers

What term is used for the combination of various minerals that form rocks?

Rock-forming minerals Signup and view all the answers

How much of Earth's volume does the core constitute?

15% Signup and view all the answers

What materials make up the upper mantle compared to the lower mantle?

Solid rocks in the upper mantle; molten rock in the lower part Signup and view all the answers

Which term is often used to describe the continental crust based on its composition?

SIAL Signup and view all the answers

Study Notes

Earth's Crust Composition

The Earth's outer layer is solid, while the interior consists of hot, molten material.
Approximately 98% of the Earth's crust is made up of eight key elements: oxygen, silicon, aluminum, iron, calcium, sodium, potassium, and magnesium.

Abundance of Elements

Oxygen constitutes 46.6% of the Earth's crust by weight.
Silicon accounts for 27.72%, followed by aluminum at 8.13%, and iron at 5.00%.
Other elements include calcium (3.63%), sodium (2.83%), potassium (2.59%), and magnesium (2.09%).
Remaining elements collectively make up 0.41% of the crust.

Minerals and Rocks

The Earth's crust is composed of rocks, which are formed from minerals.
Rock-forming minerals are common and crucial for the majority of rocks.
Minerals are inorganic solids with specific internal structures and defined chemical compositions.

Crust Structure

The average thickness of the continental crust ranges from 30 to 40 km.
Oceanic crust thickness is significantly less, measuring 5 to 6 km.
Continental crust primarily consists of silica (Si) and aluminum (Al), known collectively as SIAL.
Oceanic crust is mainly composed of silicon (Si) and magnesium (Mg), referred to as SIMA.

Mantle Characteristics

The mantle is located beneath the crust, spanning approximately 2,900 km in thickness and making up 84% of Earth's volume.
The upper mantle contains solid rocks, while the lower mantle consists of molten rock called magma.
The mantle's primary constituent elements are silicon and magnesium (SIMA).

Core Composition

The core is the innermost layer, predominantly made of nickel (Ni) and iron (Fe), also known as NIFE.
The core reaches temperatures around 6,000 °C and constitutes nearly 15% of Earth’s volume.
The core consists of two layers: a solid inner core and a liquid outer core.

Rock Classification

Rocks are categorized based on their formation into igneous, sedimentary, and metamorphic types.
They play vital roles as sources of fuel, construction materials, and food nutrients.

Key Earth Layers

The three major components of the Earth are the crust, mantle, and core.

Glossary of Terms

Asteroids: Small rocky bodies orbiting the sun.
Atmosphere: The air envelope surrounding Earth.
Core: Central layer, mainly composed of nickel and iron.
Crust: Outer layer of the Earth.
Mantle: Intermediate layer between the crust and core.
Magma: Molten rock beneath Earth's surface.
Minerals: Naturally occurring inorganic solids with a defined chemical composition.

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Description

Explore the physical characteristics of the Earth in this Grade 7 quiz. Learn about the elements that compose the Earth's crust and their states in different layers. Test your knowledge on the most abundant elements and their significance.