Unit 1 Lesson 1 Earths Spheres Copyright Houghton

Unit 1 Lesson 1 Earth’s Spheres Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 1 Lesson 1 Earth’s Spheres 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. Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 1 Lesson 1 Earth’s Spheres 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. Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 1 Lesson 1 Earth’s Spheres What is the geosphere? • 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. Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 1 Lesson 1 Earth’s Spheres What is the geosphere? • Describe the characteristics of the layers of Earth. Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 1 Lesson 1 Earth’s Spheres 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. Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 1 Lesson 1 Earth’s Spheres 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. Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 1 Lesson 1 Earth’s Spheres 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. Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 1 Lesson 1 Earth’s Spheres What is the atmosphere? • 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. Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 1 Lesson 1 Earth’s Spheres What is the atmosphere? • 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. Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 1 Lesson 1 Earth’s Spheres 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. Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 1 Lesson 1 Earth’s Spheres 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. Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 1 Lesson 1 Earth’s Spheres How do Earth’s spheres interact? • 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. Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 1 Lesson 1 Earth’s Spheres How do Earth’s spheres interact? • How many parts of the Earth system can you identify in this image? How do they interact? Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 1 Lesson 1 Earth’s Spheres 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. Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 1 Lesson 1 Earth’s Spheres What is the source of Earth’s energy? • 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. Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 1 Lesson 1 Earth’s Spheres What is the source of Earth’s energy? • Trace the flow of energy through Earth’s system. Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 1 Lesson 1 Earth’s Spheres What is the source of Earth’s energy? • 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. Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 1 Lesson 1 Earth’s Spheres 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. Copyright © Houghton Mifflin Harcourt Publishing Company