How Do Scientists Measure Earthquakes?

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Objective

SWBAT graph earthquake magnitudes and draw simple conclusions.

Big Idea

Earthquakes make the Earth rock 'n roll. Scientists measure an earthquake's intensity on a scale. We can graph that information to learn about earthquakes.

Teacher Notes

Activity Description

This lesson begins by asking the students about how they think scientists go about measuring earthquake intensity and why they collect this data.  Then the students graph earthquake data from 3 different days.  We watch a video that tells about earthquakes and how scientists measure their magnitude.  They practice using their data to answer basic questions.  Then they must use all 3 graphs to draw conclusions about the data.  They also get to ask and answer their own questions about the graphs to the class.  

NGSS/Common Core Connections

In the NGSS, the children are expected to use information from several sources to provide evidence that Earth events can occur quickly or slowly.  In order to do this, they need to have a basic knowledge of how events shape the land.  In this lesson, they will be learning specifically about earthquakes and how they create change very quickly.

As part of the science practices, they will using mathematical thinking to help them describe the natural world.  They will be describing, measuring and comparing quantitative attributes of earthquake magnitudes to display the data using simple graphs.  As part of a cross-cutting concept, this lesson helps the children to understand that some things stay the same and others change.  These changes may happen quickly or slowly.  They will also be working towards science practice 4, analyzing and interpreting data.

Materials

Engage

5 minutes

I show the students this website that has indicators on a map showing the earthquakes that have happened recently.  This is a University of Illinois earthquake website, but it links to the USGS website.  You can view the earthquakes that have happened in the last 24 hours.  If you go to the USGS website, you can set the parameters for the earthquakes you would like to have displayed by time and/or by magnitude.

I want the children to have a discussion about the questions below with a partner.  So I have them discuss the questions with their turn and talk partners.  I use turn and talk partners when I would like the children to have a short discussion by getting into partner groups quickly.

On the website, it says that geologists, or scientists who study the Earth,  have very sensitive equipment that monitors earthquake activity worldwide.   How do you think geologists measure how strong they are?  How can we easily compare earthquakes? Why would geologists collect this data? Please discuss these questions with your turn and talk partner.

I want the children to be thinking about how we could possibly measure something scientifically.  It gets them thinking like a scientist.  It also prepares them for today's lesson, which is graphing the magnitude of earthquakes by using the information found on the USGS website.

Explore--Graphing Earthquakes

15 minutes

I want to introduce the children to using this Earthquake graph sheet and the earthquake information sheets (see resources).  It contains some numbers on it that might confuse the kiddos.  So I explain what the decimals mean, not too much in detail, since I don't want to confuse them.  But they do need to use those numbers so they do need to be familiar with them. 

You are going to be working like a geologist and take a close look at earthquakes that have happened in the last few days in the world.  I have looked at the USGS website and retrieved information about earthquakes.  We are going to be taking this information and create graphs from it.  Then we will use the graphs to compare information.

Using real-life data and information makes the children really "buy into" this project (see reflection).  

Take out the sheet that has a bunch of numbers and words on it.  Look at the column with numbers on it.  It should have the abbreviation MAG above the column.  The letters MAG stand for the word magnitude.  The magnitude of an earthquake tells scientist how strong it was.  Each number in the column stands for how strong an earthquake was measured using scientific equipment.  The higher the number, the greater the magnitude or strength of the earthquake.  An earthquake with the number of 6 would be much stronger than a number of 3.  

The numbers start at a single number, like 3,  and then it increases slowly or gradually.  So you will see the number 3, then 3.1, then 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, etc.  Each time the earthquake is stronger, we add another number behind the decimal point.  So which do you think is a stronger earthquake, 3.1 or a 3.9?  For this task, earthquakes with any magnitude beginning with the same number will be in the same category on the graph.  So any earthquake between 3 and 3.9 will be grouped together.

This sounds complicated to explain, but my children picked up on the idea easily.

Now we are going to use this data to graph the magnitude of earthquakes that have happened in the past 3 days.  I have given each partner group 3 sheets of earthquake data.  You have sheet number 1,2 and 3.  Sheet #1 shows the earthquakes that measured above 2.5 magnitude on April 17, sheet #2 on April 18 and sheet #3 on April 19.

How do you think we could take this information and put it into a graph?

We come up with the idea of highlighting the same magnitudes with the same color.  Then using that same color to color the corresponding bar on the graph (see earthquake graph student sample).  To help them transfer the raw information from the USGS information to a graph, I found they needed an extra step (see reflection), so I added an Earthquake Tally Chart

We start the graphing together to make sure the children get the right idea.  My class has had a good amount of practice on graphing since we graphed data in our biodiversity unit and also graph spelling progress. I have taught them to outline all around the bar that they will be coloring in.  This eliminates kids that color the bars randomly and forget where to stop at the top of the graph.  

We do the first two bars of data as a whole class so they understand how to do it.  Then after I see that they have the right idea, they complete the rest of the graphing with their partner.  My kids love doing this!  This video clip shows a partner group checking their data and coloring in their graphs.   The boys in this video clip are double checking their information before they graph, which I am very peased to see.

Explanation

15 minutes

Just for fun we take a look at how people first made an invention to help them predict earthquakes.  Here is a photo of a Chinese Earthquake Predictor made in 132 A.D.  Here is an explanation of it and how it used to help people from long ago predict earthquakes.  

Then we watch a StudyJams video that tells about earthquakes and about the scientists who study them.  It explains how scientists use Richter scales to study the magnitude, or size, of the earthquake.   

Elaboration

15 minutes

Next we analyze and interpret the information we have graphed by completing three additional tasks.  The children answer some questions about the graph, they draw conclusions and then they write their own question and answer.

First the children simply answer the questions on earthquake graphing questions sheet.  The questions refer to the information sheets by number.  I kept it "generic" in case you wanted to use more recent earthquake information that has occurred on the days you are using this lesson.

Scientists collect data, like how you just have, and then try to use this data to help them see relationships and draw conclusions from it.  This helps them understand the natural world, such as earthquakes.  This helps them to understand them better.  You are going to be doing this, too.

I want the children to realize that the information that they have collected has meaning.  We have to figure that meaning out.  This helps them start to understand the importance of analyzing and interpreting data.

I would like you to use your graphs to find the answers to the questions on the sheet.  You may work with your partner to find the answers.  You will need to number your graphs to match the number on the sheets.  So the graph that tells about the earthquakes on April 17 will be graph#1, April 18 will be graph #2 and April 19 will be graph #3.  Please put the number of the graph at the top of the page.

Here is a clip of partners working together to find answers to the questions. Click here to see how a student uses math skills to help him answer the question.

For question 4 and 5 you are going to have to compare all 3 graphs.  So please lay out your graphs so you can see all 3 of them at once.  This will help you compare them.

In this part of the worksheet the students compare the graphs to make inferences using the information and draw conclusions.  Drawing conclusions can be very difficult for children at this level, but also very necessary so they start building a base for thinking scientifically.  In this video clip I love how the boy is delighted to have figured out the information without teacher help.

I walk around to see which partner groups need help in this task. These two girls worked hard to figure out the answer.  They had to examine all 3 graphs carefully in order to extrapolate the information necessary.  The clip is longer than usual since it shows the whole process of what they did and how I went about helping them come to the conclusion I wanted them to arrive at.  Other groups just needed a push in the right direction.

Now I want you to be like a teacher.  You need to write a question that can be answered by looking at one of the graphs.  Just like teachers do, you will also need to write the answer to your question.  

The kids love this part since they feel like they are the teacher and get to create a great question.  It gets them very motivated, and it is great practice since they also answer their own question.  When they finish, the students take turns asking each other their questions and then calling on another peer to answer their question.  They love it!  Here is a boy asking his own question.  Not only was he thrilled to be asking the question, but notice the excitement that the boy next to him had to answer his question.  He could hardly contain himself! 

 

Wrap-Up/Evaluation

10 minutes

To wrap up the lesson we talk about why and how graphing data is important to scientists.

  • Why do scientist graph and analyze data about earthquakes?  
  • How can this information be useful?  
  • Which did you find easier to read--the chart or the graph that you made?  Why?  

 

Check out this video clip to see how a girl explained the helpfulness of using graphs as opposed to a chart.

We check the graphs and question sheets for accuracy.  Then we glue the graphing sheets and the answer sheet into their science journal.