Earth's Systems

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Questions and Answers

What percentage of the Earth's core is made up of iron metal?

95 percent

90 percent

75 percent

85 percent (correct)

What is the main component of the remaining 15 percent of the Earth's core?

Water

Nickel metal (correct)

Gas

Rock

Why is the Earth's core metal?

Because it's in the center of the Earth

Because it's made of rock

Because it's magnetic (correct)

Because it's liquid

What would happen if the Earth's core were not metal?

The Earth would not have a magnetic field Signup and view all the answers

Why do scientists know that the outer core is liquid and the inner core is solid?

Because S-waves stop at the inner core Signup and view all the answers

What causes convection currents in the outer core?

Heat from the inner core Signup and view all the answers

What is the theory that deals with the dynamics of the Earth's outer shell?

Plate tectonics Signup and view all the answers

What is the typical thickness of the lithosphere?

100 km Signup and view all the answers

What is the explanation for the shift of light from distant galaxies to lower frequencies?

The galaxies are moving away from us Signup and view all the answers

What is the term used to describe the rapid expansion and cooling of the universe?

The Big Bang Signup and view all the answers

What is the composition of the universe after the Big Bang?

Only simple matter Signup and view all the answers

What causes the contraction of a nebula?

The mutual gravity of all the atoms Signup and view all the answers

What happens to the core of the nebula as it contracts?

It heats up Signup and view all the answers

What is the energy source of a star?

Nuclear fusion Signup and view all the answers

What stops the gravitational contraction of a proto-star?

The release of energy from nuclear fusion Signup and view all the answers

What is the term used to describe the formation of galaxies?

Galactic formation Signup and view all the answers

What is the main function of the atmosphere?

To keep the planet warm and provide oxygen and carbon dioxide Signup and view all the answers

Approximately what percentage of the Earth's water is saline?

96.5% Signup and view all the answers

What is the hydrosphere?

The system of liquid water on Earth Signup and view all the answers

What is the cryosphere?

The system of ice and glaciers Signup and view all the answers

How do the Earth's systems interact?

They overlap and are interconnected, affecting each other Signup and view all the answers

What happens when a parcel of air in the atmosphere becomes saturated with water?

Precipitation, such as rain or snow, can fall to Earth's surface Signup and view all the answers

What is the result of erosion and weathering over time?

The breakdown of large rocks into smaller ones, such as sediments Signup and view all the answers

How can the cryosphere be involved in erosion?

Through the scouring of bits of rock from the bedrock beneath glaciers Signup and view all the answers

What is the purpose of measuring the abundances of parent and daughter isotopes in a sample?

To determine the age of the sample Signup and view all the answers

What happens to the argon gas when the lava is still molten?

It escapes into the atmosphere Signup and view all the answers

What is the 'radiometric clock'?

The process of radioactive decay Signup and view all the answers

What is the half-life of an isotope?

The time it takes for half of the parent isotope to decay into daughter isotopes Signup and view all the answers

What happens when the quantities of the parent and daughter isotopes are equal?

One half-life has occurred Signup and view all the answers

What was the surface of the Earth like after its initial formation?

Extremely hot and entirely liquid Signup and view all the answers

How old is a bone if there is three times less 14C than 14N in the bone?

11,460 years old Signup and view all the answers

When did the first recorded history of rocks appear?

During the Archean Eon Signup and view all the answers

Why is radiocarbon dating not useful for measuring things that were formed in the distant geologic past?

Because the amount of 14C left in the bone will be too small to measure accurately Signup and view all the answers

What is the approximate age of the oldest discovered fossils?

3.5 billion years ago Signup and view all the answers

What is the age of a bone if the measured abundance of 14C and 14N in the bone are equal?

5,730 years old Signup and view all the answers

What was the result of the Cyanobacteria's photosynthetic activity?

A rapid upsurge in atmospheric oxygen Signup and view all the answers

What is the characteristic of the 'boring billion' stage of Earth's history?

A period of relative stability of the ocean carbon reservoirs Signup and view all the answers

What geological event occurred during the Mesoproterozoic Era?

The break-up of the supercontinents Signup and view all the answers

What is notable about the Neoproterozoic Era?

It is one of the most profound time periods in Earth's history Signup and view all the answers

What is the approximate age range of the Paleoproterozoic Era?

2.5 – 1.6 billion years ago Signup and view all the answers

Study Notes

The Five Systems of the Earth

The atmosphere is an envelope of gas that keeps the planet warm and provides oxygen for breathing and carbon dioxide for photosynthesis.
The hydrosphere is made up of liquid water, including freshwater and saltwater, and is also part of other spheres like the cryosphere and geosphere.
The geosphere includes the rocks and minerals that make up the Earth's surface and interior.
The cryosphere contains huge quantities of ice at the poles and elsewhere.
The biosphere is the zone of life on Earth and is made up of all living organisms.

The Atmosphere and Hydrosphere

96.5% of the water on Earth is saline and not drinkable without processing.
The majority of fresh water on Earth is locked up in the cryosphere.
Precipitation connects the hydrosphere with the geosphere by promoting erosion and weathering.

The Core and Plate Tectonics

The core is about 85% iron metal and 15% nickel metal.
If the core were not metal, the planet would not have a magnetic field.
Plate tectonics is the theory that deals with the dynamics of Earth's outer shell, the lithosphere.
The lithosphere is broken up into seven large plates and several smaller ones that move relative to each other.

The Big Bang Theory and Stellar Evolution

The Big Bang Theory states that the universe began as an explosion around 10-15 billion years ago.
Galaxies formed in areas of higher concentrations of hydrogen and helium, and stars formed within the galaxies in areas of highest concentrations.
A nebula (gas cloud) slowly contracts under gravity, causing heat and pressure to increase, eventually leading to nuclear reactions and the formation of a star.

Geological Time Scale

The Archean Eon (4-2.5 billion years ago) saw the cooling of the Earth's surface, the solidification of the oceans and continents, and the appearance of life.
The Paleoproterozoic Era (2.5-1.6 billion years ago) saw the formation of tectonic plates, the shift of landmasses, and the appearance of cyanobacteria, which brought about the Great Oxidation Event.
The Mesoproterozoic Era (1.6-1 billion years ago) saw the break-up of supercontinents and the formation of new continents, as well as the first noted case of sexual reproduction and the probable appearance of multicellular organisms.
The Neoproterozoic Era (1 billion-542.0 million years ago) saw significant geochemical activity, the formation of new oceans, and the probable appearance of green plants.

Radiometric Dating

Radioactive isotopes in rocks and organic matter can be used to determine their age.
The rate of decay for many radioactive isotopes has been measured and does not change over time.
The half-life of an isotope is the amount of time it takes for half of the parent isotope to decay into the daughter isotope.

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Description

Quiz about the five systems of the Earth, including the atmosphere, hydrosphere, lithosphere, biosphere, and cryosphere. Learn about their interactions and importance.