Layers of the Earth I

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SWBAT sequentially identify the layers of the Earth and their relative densities | SWBAT evaluate how density affects the interior of the Earth

Big Idea

Students will take use their newfound knowledge of density to apply relative densities to the interior of the Earth and its associated layers. Students will also analyze how the density of each layer is primarily affected by its elemental composition.

Lesson Introduction

[Note: For embedded comments, checks for understanding (CFUs), and key additional information on transitions and key parts of the lesson not necessarily included in the below narrative, please go to the comments in the following document: 2.4 - Layers of the Earth I (Whole lesson w/comments). Additionally, if you would like all of the resources together in a PDF document, that can be accessed as a complete resource here: 2.4 - Layers of the Earth I (Whole lesson)[PDF]. Finally, students may need their Earth Science Reference Tables [ESRT] for parts of the lesson (a document used widely in the New York State Earth Science Regents course) as well.]

This lesson on layers of the Earth asks students to, in their lab groups, make a collaborative poster presentation on a specific layer of the Earth (there are four total groups: crust, mantle, inner core, and outer core). The following day (see Lesson 2.5), students actually present their information to the class, and in turn, receive information about the other layers of the Earth. 

Do Now & Objective(s)

10 minutes

Students come in silently and complete the (attached) Do Now. After time expires, we collectively go over the responses, usually involving a series of cold calls and volunteers. Finally, I then ask a student to read the objective out loud before beginning the lesson. 

Presentation Overview

10 minutes

In the Presentation Overview, I present the information provided on the handout - students have the choice to do either a traditional poster presentation in the front of the class, or create a PREZI/PowerPoint for students to take notes from. The Presentation Overview resource has both guiding questions and required information for students to include in their presentations, which were created by me to give some focus and clarity to what the students actually say during the presentations. 

One of the overarching themes of the next two days is the notion that these properties, beyond the crust, are inferred. Specifically, scientists have utilized seismic waves to determine the various properties of each layer. I introduce this concept to them in the introductory paragraph in the Presentation Overview resource, but it's also something each group will collectively tackle in their presentations. Another prime area of focus is the concept of increasing temperature, density, and pressure with depth. The guiding questions ask them to identify the relative densities, pressures, and temperatures of adjacent layers of the Earth, and each group honing in on this allows them to see this theme repeatedly when preparing and presenting for their projects. 

Group Work & Poster Creation

25 minutes

In this section, I give each group some uninterrupted group time to organize themselves and think about both what and how to present the material in the best way possible (using the Layers of Earth Notes resource to help them). When circulating (I try to do a quick initial check-in with each group before prioritizing groups that may need a bit of support), I try to hone in on the idea that the presentation is not just presenting the material - i.e. the time shouldn't be just "finding facts," but actually preparing for the presentation. Thinking about what you're going to say, how you're going to say, who in the group is going to say it are important elements for an effective presentation, and I think they're all relevant for the groups to hear. 

Additionally, I usually stress that this is something needs to be completed this period. I warn them that they'll get a final 5-7 minutes of group preparation time next class, but the facts and process of their presentation should be completed by the end of their respective work time on this day. 

To help guide the groups and focus their work, I give them each a piece of text with many of the facts they need for their presentations already embedded (located in the Layers of Earth Notes). Additionally, I point them to Page 10 in their Earth Science Reference Tables [ESRT], which has a few images and graphs with very pertinent information.


5 minutes

[Note: Unlike most of my lessons, this lesson doesn't have an exit ticket, as the material covers two days]

Since there is no exit ticket, I usually wrap up a bit closer to the actual bell for the day. I ask one person in each group to quickly put their posters and/or computers in a designated shared space in the back of the room, and then I have them transition out of their laboratory groups into their normal seating arrangement (see reflection in this section for more information here). I then make sure they know that the Layers of Earth Practice section is for homework (I want to maximize their work time, which is why they don't really work on it in class), and once students are cleaned up and ready, if there's extra time, I usually ask a student or two to reflect on their group process and preparation (i.e. "How did it go today?", "Did your group run into any conflicts?") before they transition out of the room when the bell rings.