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Praxis (7005) - Elem. Ed: Science > 1A Earth System Structure and it's Spheres > Flashcards

1A Earth System Structure and it's Spheres Flashcards

Learn the structure and properties of solid Earth and its four spheres: atmosphere, biosphere, geosphere, and hydrosphere.

1
Q

What are the three layers of the Earth?

A
  • Crust
  • Mantle
  • Core

The Earth’s layers are distinguished by their chemical composition and physical state.

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2
Q

What is the outermost layer of rock which supports all life?

A

Crust

The crust is the thinnest layer of the Earth and is made of rocks, minerals, and metals.

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3
Q

Describe the composition of the Earth’s crust.

A

It is composed of solid rock, primarily made up of oxygen, silicon, aluminum, and iron.

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4
Q

What are the two types of crust found on Earth?

A
  1. Continental crust - forms the continents.
  2. Oceanic crust - forms the ocean basins.
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5
Q

What is the difference between the Earth’s continental and oceanic crust?

A
  • The Continental crust - thicker (25-100km) but older, less dense and is composed mainly of granite.
  • The Oceanic crust - thinner (5-10km) but heavier, denser and is composed mainly of basalt.

Oceanic is denser because it is made of iron and magnesium rich basalt. Continental is less dense because it is made of granite.

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6
Q

What is magma and where is it found?

A

Magma is the molten, or semi-molten material which forms igneous rock. It is found in the upper mantle, or asthenosphere.

Magma can also accumulate in magma chambers within the crust.

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7
Q

What is the difference between magma and lava?

A
  • Magma - molten rock beneath the Earth’s surface.
  • Lava - magma that has erupted onto the surface.
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8
Q

What scientific principle causes the different layers of the Earth?

A

Density stratification

During Earth’s formation, denser materials sank to form the core while lighter materials formed the crust and mantle.

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9
Q

How does magma form?

A

When rocks in the Earth’s mantle melt due to an increase in temperature, a decrease in pressure, or the addition of water, which lowers the melting point of the rocks.

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10
Q

What makes up about 84% of the Earth’s total volume?

A

Mantle

The mantle extends from just beneath the crust to the outer core, approximately 2,900 km deep.

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11
Q

What is the solid metal inner core of the Earth primarily made of?

A

Iron and nickel.

The inner core is solid due to the immense pressures despite its high temperatures.

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12
Q

What creates the Earth’s magnetic field?

A

A combination of convection currents of molten iron and nickel in the outer core, and the rotation of Earth on its axis.

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13
Q

Describe the 2 layers of the upper mantle.

A
  1. The rigid upper layer called the lithospheric mantle which is part of the lithosphere.
  2. The lower layer called the asthenosphere which is partially molten plastic type layer which moves under high pressure.
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14
Q

What layer of the mantle moves like a convection oven with the current pushing hot molten magma towards the Earth’s surface?

A

The asthenosphere.

This movement drives the movement of the tectonic plates.

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15
Q

How many layers does the Earth’s core have?

A

Two

The inner core and outer core.

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16
Q

Distinguish between the outer core and the inner core.

A
  • The outer core is liquid, composed mainly of iron and nickel.
  • The inner core is solid and primarily made of iron and nickel.

The Bullen discontinuity is a boundary within the Earth’s interior that separates the outer core from the inner core.

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17
Q

What is the state of matter of the Earth’s outer core?

A

Liquid

It is composed of Iron and Nickel.

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18
Q

What is the lithosphere?

A

The rigid outer layer of the Earth, consisting of the crust and the uppermost part of the mantle.

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19
Q

What are tectonic plates and how are they related to the Earth’s crust?

A

Large, rigid pieces of the lithosphere that move and interact at their boundaries, causing geological activity.

Generally composed of both continental and oceanic lithosphere.

20
Q

Describe the structure of the lower mantle.

A

It extends from the asthenosphere to the outer core and is composed of solid, high-pressure minerals.

It is the largest of the Earth’s layers extending to 2900km.

21
Q

What causes the creation of mountains and eruptions of volcanoes on Earth?

A

Tectonic plate movements and interactions, such as collisions.

Tectonic plates move due to convection currents in the mantle.

22
Q

How do the huge slabs of lithosphere (called tectonic plates) interact?

A

The lithosphere is divided into tectonic plates that move on the semi-fluid asthenosphere, causing geological activities like earthquakes and volcanic eruptions.

23
Q

What scientific force causes the different layers of the Earth?

A

Gravity

Gravity pulls dense materials down towards the center of the Earth, forming the layers.

24
Q

What is the composition of the Earth’s mantle?

A

Mainly of silicate minerals rich in iron and magnesium.

25
Q

What causes earthquakes, volcanoes, and other seismic activity in the Earth’s crust?

A

The movement and interaction of tectonic plates.

These activities occur mainly along plate boundaries.

26
Q

What is geodesy?

A

The study of Earth’s shape and size, focusing on its geometric shape, orientation in space, and gravity field.

27
Q

What is the shape of Earth according to geodesy?

A

An oblate spheroid, flatter at the poles and rounder at the equator.

It is flatter at the poles due to centrifugal force.

28
Q

What affects the shape of the Earth?

A
  • Gravity
  • Stress
  • Density
29
Q

What are the four spheres of the Earth?

A
  1. Atmosphere (air)
  2. Biosphere (living things)
  3. Geosphere (land)
  4. Hydrosphere (water)

The four spheres are responsible for the climate, geological processes, and all life on Earth.

The geosphere includes the lithosphere but also extends deeper into the Earth’s interior.

30
Q

What is the atmosphere and describe its role.

A

The layer of gases surrounding the Earth, essential for weather, climate, and protecting life from harmful solar radiation.

31
Q

What are the main components of the atmosphere?

A
  • nitrogen (78%)
  • oxygen (21%)
  • trace gases

Trace gases include argon, carbon dioxide, and water vapor.

32
Q

What is the biosphere?

A

The sphere that includes all living organisms on Earth, from the deepest oceans to the highest mountains.

All living things on Earth; biotic and originates from the Greek prefix bio- meaning ‘life’.

33
Q

What is the geosphere?

A

The solid part of the Earth, including rocks, minerals, and landforms, extending from the surface to the core.

34
Q

What is the hydrosphere?

A

All the water on Earth, including oceans, lakes, rivers, glaciers, groundwater, and water vapor in the atmosphere.

The state of water in the hydrosphere is influenced by temperature and pressure.

35
Q

How do the atmosphere and hydrosphere interact?

A

Through the water cycle, involving processes like evaporation, condensation, precipitation, and runoff.

36
Q

What forms can water take in the hydrosphere?

A
  • Liquid forms (e.g. oceans)
  • Solid forms (e.g. glaciers)
  • Gaseous forms (e.g. water vapor)
37
Q

How do plants (biosphere) interact with the geosphere?

A

Plant roots anchor into the soil and absorb nutrients and water from the geosphere, facilitating growth and stability.

38
Q

How does the geosphere affect the atmosphere?

A

Volcanic eruptions release gases and particles into the atmosphere, impacting air quality and climate.

39
Q

How does the hydrosphere impact the biosphere?

A

It provides essential water and transports nutrients for all living organisms, supporting life and ecosystems.

40
Q

Give an example of an interaction involving all four spheres.

A

A tree (biosphere) absorbs water (hydrosphere) through its roots in the soil (geosphere) and releases oxygen and water vapor into the air (atmosphere) through photosynthesis and transpiration.

41
Q

Describe the composition and behavior of the Earth’s mantle.

A

It is composed of solid rock that flows over long periods of time, exhibiting plastic behavior. It is mainly composed of silicate minerals.

42
Q

How do scientists study the interior structure of the Earth?

A

Through techniques such as seismic waves, which provide information about the density and composition of Earth’s layers.

43
Q

What creates the Earth’s magnetic field?

A

The movement of the liquid outer core.

44
Q

What role does the Earth’s magnetic field play in its structure?

A

It helps shield the planet from solar radiation and aids navigation.

The Earth’s magnetic field is generated by movements in the liquid outer core.

45
Q

What are the 5 main layers of Earth’s atmosphere?

A
  1. Troposphere
  2. Stratosphere
  3. Mesosphere
  4. Thermosphere
  5. Exosphere

Praxis (7005) - Elem. Ed: Science (36 decks)

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