unit 1 lesson 1 earth’s spheres copyright © houghton mifflin harcourt publishing company

Unit 1 Lesson 1 Earth’s Spheres

Copyright © Houghton Mifflin Harcourt Publishing Company

What on Earth?


What is the Earth system?

• A system is a group of related objects or parts that work together to form a whole.

• The Earth system is all of the matter, energy, and processes within Earth’s boundary.

• Earth is a complex system made of living and nonliving things, and matter and energy continuously cycle through the smaller systems.


What is the geosphere?

• The geosphere is the mostly solid, rocky part of Earth. It extends from the center of Earth to the surface of Earth.

• The thin, outermost layer of the geosphere is called the crust. It is made mostly of silicate minerals.

• Oceanic crust is 5 to 10 km thick. Continental crust is 35 to 70 km thick.




• The mantle is the layer that lies below the crust. It is about 2,900 km thick.

• The mantle is made of very slow-flowing, solid rock, consisting of silicate minerals that are denser than the silicates in the crust.

• Earth’s central part, called the core, has a radius of about 3,500 km. It is made of iron and nickel and is very dense.




• Describe the characteristics of the layers of Earth.



Got Water?


What is the hydrosphere?

• The hydrosphere is the part of Earth that is liquid water.

• Oceans, lakes, rivers, marshes, groundwater, rain, and the water droplets in clouds are part of the hydrosphere.

• Water on Earth is constantly moving. It even moves into and out of living things.


What is the cryosphere?

• The cryosphere is made up of all of the frozen water on Earth.

• Snow, ice, sea ice, glaciers, ice shelves, icebergs, and permafrost are all part of the cryosphere.

• Changes in the cryosphere can play an important role in Earth’s climate and species’ survival.



What a Gas!


What is the atmosphere?

• The atmosphere is a mixture of mostly invisible gases that surround Earth.

• It extends outward about 500 to 600 km from Earth’s surface, but most of the gases lie within 8 to 50 km of Earth’s surface.

• The atmosphere is about 78 percent nitrogen, 21 percent oxygen, and 1 percent many other gases.



• Minor gases in the atmosphere include argon, carbon dioxide, and water vapor.

• The atmosphere contains the air we breathe.

• It also traps some energy from the sun, which helps keep Earth warm enough for living things to survive and multiply.




• Some gases of the atmosphere absorb and reflect harmful ultraviolet (UV) rays from the sun, protecting Earth and its living things.

• The atmosphere also causes space debris to burn up before reaching Earth’s surface and causing harm.



What is the biosphere?

• The biosphere is made up of living things and the areas of Earth where they are found.

• Organisms usually need oxygen or carbon dioxide to carry out life processes.

• Liquid water, moderate temperatures, and a stable source of energy are also important for most living things.



What’s the Matter?


How do Earth’s spheres interact?

• All of the five spheres of Earth interact as matter and energy change and cycle through the system.

• A result of these interactions is that they make life on Earth possible.



• Earth’s spheres interact as matter moves between them. In some processes, matter moves through several spheres.

• Earth’s spheres also interact as energy moves from one sphere to another, and back and forth between spheres.




• How many parts of the Earth system can you identify in this image? How do they interact?



Balancing the Budget


What is the source of Earth’s energy?

• Almost all of Earth’s energy comes from the sun.

• A tiny fraction of Earth’s energy comes from ocean tides and geothermal sources such as lava and magma.



• Energy is transferred between Earth’s spheres, but it is not created or destroyed.

• Any addition of energy to one sphere must be balanced by an equal subtraction of energy from another sphere.

• The movement of energy through Earth’s system forms an energy budget.




• Trace the flow of energy through Earth’s system.




• When Earth’s energy flow is balanced, global temperatures stay relatively stable over long periods of time.

• Sometimes, changes in the system cause Earth’s energy budget to become unbalanced.



What can disturb Earth’s energy budget?• An increase in greenhouse gases traps more

energy in the atmosphere and decreases the amount of energy radiated out to space.

• Polar ice and glaciers reflect sunlight. When the ice melts, the exposed water and land absorb and then radiate more energy than the ice did.

• In each case, Earth’s atmosphere becomes warmer, which may lead to climate changes.



unit 1 lesson 1 earth’s spheres copyright © houghton mifflin harcourt publishing company

Documents

earths sphereswhat

earth system

earths surface

surface of earth

earths climate

earths boundary

earths central

layers of earth