Earthquakes (Day 1/2)

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Objective

SWBAT define an earthquake and use the Mercalli Scale to determine the approximate epicenter of an earthquake

Big Idea

Students will take on their first natural disaster in this lesson. This lesson introduces students to the phenomenon of earthquakes as the creation of seismic waves caused by friction along plate boundaries and faults.

Lesson Introduction

This is another lesson with content cross-cutting over two days (see tomorrow's lesson here). The first part of the lesson today involves a few things: students explore the potential devastation caused by earthquakes in a brief video, learn some basic earthquake facts in a scientific text, and analyze how earthquakes are measured. They then begin a lab which has them chart out and diagram earthquake intensity based upon reports of damage by earthquake survivors. Additionally, for the first time (but not the last time), they're going to be introduced to the term isolines. Isolines are lines that connect other points of equal value. So if one were to connect all elevations on a landscape with an elevation of 800 feet, an isoline would be used. In this lab, they are going to be used to identify all points with the same amount of earthquake damage. Finally, there are special materials and preparation needed for this lesson, which are posted in the Lab Introduction section below (they are also posted here).

Materials:

[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: 2.6 - Introduction To Earthquakes (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: 2.6 - Introduction To Earthquakes (Whole lesson). 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.]

Do Now & Objective(s)

10 minutes

Students come in silently and complete the (attached) Do Now. In this case, the Do Now is a review of some "hot standards" from the current unit - relating mostly to the interior of the Earth, with a question from an earlier unit thrown in for good measure. After time expires (anywhere from 2-4 minutes depending on the type of Do Now and number of questions), we collectively go over the responses (usually involving a series of cold calls and/or volunteers), before I call on a student and ask them to read the objective out loud to start the lesson.

As a general note, the Do Now serves a few purposes:

  1. It serves as a general review of the previous day's material; 
  2. It is a re-activation of student knowledge to get them back into "student mode" and get them thinking about science after transitioning from another content area or alternate class;
  3. as a strategy for reviewing material students have struggled with (for example, using this as a focused review for material that they have struggled with on unit assessments or recent quizzes); and,
  4. It is an efficient and established routine for entering the classroom that is repeated each day with fidelity (I never let students enter the classroom talking. While it may seem potentially severe to have students enter silently each day, this is both a school wide expectation and a key component of my classroom. In many respects, I find that students readily enjoy the focus that starting with a quiet classrooms brings each day).

Earthquake Video & Introduction

15 minutes

In the first part of this two-day lesson, I have a “hook” to give students a glimpse into the destructive power of earthquakes. We start with a quote from a survivor of the earthquake that struck Port-Au-Prince in 2010, which can be found at the top of the first page of the Video Notes & Introduction resource. (Note: Please refer to attached resource in the Lesson Introduction for the handout and embedded comments for this section) After the quote, we transition into a brief, 3-4 minute video (link here) that introduces the science of earthquakes.

Before the video starts, I ask them to use the note-taking space in the handout to select and write down the 3-5 most pertinent earthquake facts from the video. After the video, I have them partner up and take an additional 1-2 minutes to compare their facts, make any modifications/additions/deletions as necessary, and then be prepared to share what their most important fact from the video is. 

Video link is here

Earthquake Notes

20 minutes

The next section on Earthquake Notes introduces key vocabulary, concepts around earthquakes, and some information on measuring earthquake magnitude and intensity. 

For this section, I actually have students pair up and go through this together - I don't generally do this as a whole-class activity. After giving them some time to work through this in partners, we come back together to go over the embedded checks for understanding/questions (as mentioned above, please refer to the embedded Word document in the Lesson Introduction for those comments). I then go over the chart on the final two pages, which correlates the Mercalli Intensity and Richter Scale magnitude.

As a note, the charts themselves are very information dense, so I try to have students focus on a few key relationships. For one (and some may even arrive with this prior knowledge), there is a correlation between Mercalli Intensity and Richter Scale magnitude. While the Mercalli Scale measures the perceived damage, the Richter Scale magnitude is a quantitative measure of an earthquake's power, as the Richter scale measures displacement via seismic waves. In other words, the greater the Ricther Scale magnitude, there will also be a greater Mercalli Scale intensity the vast majority of the time. 

Secondly, I have them focus their attention on the rightmost column: Average Frequency of Occurrence. When I ask them to look here, most students very quickly grasp the inherent inverse relationship between earthquake intensity and earthquake frequency. This is the other key takeaway from the graph - the higher the intensity of the earthquake, the less frequency its occurrence in nature. When students follow the graph toward more intense Mercalli intensities/Richter scale magnitudes, the overall volume of earthquakes goes down (to the point of really intense earthquakes occurring only about 1-2 times per century). There's some more information contained here, but for the sake of time and appropriateness given the early high school context, I hone in on those two facets of the Richter/Mercalli comparison table. 

Finally, before transitioning into the lab, we look at a sample seismograph (I also use a model I have in my room, similar to this one) to demonstrate how it works before so that students have the proper context for hearing survivors' stories in the lab they're going to start. 

Lab Introduction

10 minutes

As they won't have enough time to finish the lab, I introduce the lab by showing them a completed set of Earthquake Scenario Cards. I usually cut them out, laminate them (for durability), and put them in an envelope for student use. I then introduce the lab by indicating that an earthquake has occurred, and callers are calling in to a radio station to report damage at each of their locations. It is then your job as the scientist to take the radio transcript from each caller and correlate that to a level of intensity on the Mercalli scale. They then write down their intensities on the Mercalli scale from the scenario cards on the Mercalli Scale Map provided. As an additional resource, the attached Mercalli Scale is printed as a resource for students. 

Closing

5 minutes

Since this is a two-day lesson that extends into tomorrow, there is no summative exit ticket yet, nor are they readily submitting anything for evaluation. In this case, in the last 2-3 minutes of class, I usually have students take about 30 seconds to put away any materials or deliverables that they need to in order to clear their desks (in addition to transitioning out of their laboratory groups), and I end the class at the objective at the front of the room, which is posted on the whiteboard, and ask students two questions:

  1. Do you feel that you mastered the objective for the day?
  2. Can you reiterate one thing you learned about (in this case, questions like: "Can you define a fault?" | "How are earthquake formed?")?

Once I take 2-3 individual responses (sometimes I'll ask for a binary "thumbs up/thumbs down" or something similar), I have students leave once the bell rings.