11-29-17 Earth’s Interior

Do Now: Read the text below and answer the following questions in your science notebook Frosting and sprinkled nuts cover this delicious carrot cake. But on the inside, the cake both looks and tastes very different. How many layers make up the cake? How do you know? A. 2 layers. They can be seen in the slice that is cut away, not by looking at the outside of the cake. Earth is much larger than a cake. Nevertheless, how is Earth similar to a cake? A. Like a cake, Earth has interior layers that are hidden from the outside. Do you think Earth could be sliced like a cake? A. No, it cannot. Although people can dig holes and pry away small sections of Earth, these actions reach only into Earth’s thin outer layer, not its deep interior.

Reminder: Bring your flash drive with your research & hypothesis information to class tomorrow.

Note the following change in your science fair packet The School Science Fair is no longer on 2/9. Instead, it has been moved to Wednesday, 1/24/18. As a result, the Class Science Fair will INSTEAD BE A LAB REPORT which will be a compilation of all of the assignments you will have completed anyways.

Homework: Watch the Earth’s Interior video on the textbook website.

Ch. 1, Lesson 2: Earth’s Interior Essential Questions: What are the interior layers of Earth? What evidence indicates that Earth has a solid inner core and a liquid outer core?

Earth’s Interior crust mantle lithosphere asthenosphere core magnetosphere

Clues to Earth’s Interior Deep mines and wells give scientists hints about Earth’s interior. The picture shown was taken in a cave at Mystery Falls, Tennessee, which is about 86m (~282 ft) deep. Although this seems deep, it is far above the center of Earth, which is 6,370km (~3958mi) below the surface.

Clues to Earth’s Interior Scientists learn about the inside of Earth by sending down instruments and bringing up rock samples from wells.

Temperature and pressure increase as depth increases inside Earth. The deeper you go below Earth’s surface, the higher the temperature and the higher the pressure is. The pressure increases because of the weight of the overlying rocks.

Clues to Earth’s Interior Scientists also use earthquake waves to gather information about Earth’s interior. By studying how earthquake waves move, scientists are able to infer the density and composition of the materials within Earth.

Earth’s Layers The brittle, rocky, outer layer of Earth is called the crust. The crust is the least dense layer of the geosphere and much thinner than the other layers. Earth’s outermost layer is similar to the shell of an egg: it is the thinnest layer.

There are two types of crust – continental crust and oceanic crust. The crust under oceans is called oceanic crust and is made of dense rocks containing iron and magnesium. Continental crust is much thicker than crustal rocks under the oceans.

Earth’s Layers (cont.) Earth’s mantle is the thick middle layer in the solid part of Earth, immediately below the crust. The rocks of this layer are iron- rich and denser than crustal rocks. The rocks in the uppermost layer of the mantle are brittle and rigid. Scientists group the mantle into four different layers: lithosphere, asthenosphere, upper mantle, and lower mantle.

Earth’s Layers (cont.) Scientists group the crust and the uppermost mantle into a rigid layer called the lithosphere. The rocks in the mantle’s second layer are so hot that they melt and become plastic, which means that they begin to flow. The layer of melted rock in mantle is the asthenosphere. Word Origin: asthenosphere From Greek asthenes, means “weak”; and spharia, means “sphere”

The solid rock below the asthenosphere, where high pressure prevents melting, is the upper mantle and lower mantle. The upper mantle and lower mantle form the largest of Earth’s layers

Lesson 2-2 Earth’s Layers (cont.) The dense metallic center of Earth is the core. The central part of Earth is made of metal. When the planet was young, these dense materials melted and were pulled by gravity toward Earth’s center. The core has a liquid outer core and a solid inner core. The inner core spins a little faster than the rest of Earth. (Link to the paper reporting this discovery: http://www.pnas.org/content/110/40/15914.full) It is made of iron crystals. The core causes a force field to form around Earth.

Earth’s Layers (cont.) Scientist learned that the outer core is liquid by analyzing earthquake waves. The inner core is a dense ball of solid iron crystals.

Earth’s Layers: Think (15 sec), Pair, Share (15 sec) What are the layers of Earth starting from the surface? Answer: Crust Lithosphere Asthenosphere Upper Mantle Lower Mantle Outer Core Inner Core

Earth’s Core and Geomagnetism For centuries, people have used compasses and Earth’s magnetic field to navigate. The movement of molten iron in Earth’s core makes the planet act like a giant bar magnet, with one pole near the top of the planet and one pole near the bottom. Over time, Earth’s magnetic field has varied in strength and direction

Earth’s Core and Geomagnetism (cont.) Earth’s magnetic field protects the planet against cosmic rays and charged particles from the Sun. The outer part of the magnetic field that interacts with cosmic rays and charged particles from the Sun is called the magnetosphere.

Earth’s layers include the crust, mantle, and core Earth’s layers include the crust, mantle, and core. Oceanic crust is under oceans. The continents are made of continental crust.

The mantle is Earth’s thickest layer The mantle is Earth’s thickest layer. It includes part of the lithosphere and the asthenosphere.

Earth’s core has a liquid outer core and a solid inner core.

Lesson 2 – LR1 A. greater weight B. more mass C. less mass If two materials have the same volume, the denser material will have which of these? A. greater weight B. more mass C. less mass D. less weight

Lesson 2 – LR2 A. mantle B. crust C. lithosphere D. asthenosphere Which term describes the layer of rocks within the mantle where the rock is soft enough to flow? A. mantle B. crust C. lithosphere D. asthenosphere

Lesson 2 – LR3 A. rocks B. oceanic crust C. earthquake waves What did scientists analyze to learn that the Earth’s outer core is liquid? A. rocks B. oceanic crust C. earthquake waves D. the mantle

Homework Review: Spherical Earth worksheet 1a. The atmosphere is the layer of gases surrounding Earth 1b. The hydrosphere is water found on the surface, underground, and as liquid water in the atmosphere. 1c. The geosphere is Earth’s entire solid body 1d. The biosphere includes all living things on Earth. 2. When the solar system formed about 4.6 billion years ago, gravity caused particles to come together to form spherical Earth. Earth developed distinct layers based on density – the inner layer contains the densest materials, and the outer layers contain less-dense materials.