Lessons & Units :: The Librarian Who Measured the Earth 3rd Grade Unit

Read-Aloud Lesson: The Librarian Who Measured the Earth

Lesson Plan

The Librarian Who Measured the Earth | AD840L

The Librarian Who Measured the Earth
Learning Goal
Identify the questions Eratosthenes asks throughout his life to determine the relationship between asking questions and making discoveries.
Duration
TBD
Necessary Materials
Provided:
  1. Detailed lesson plan
  2. Graphic organizer for guided practice
  3. Independent student worksheet


Not Provided:
The Librarian Who Measured the Earth

 
  1. This lesson is a close reading of the entire text. So it’s important to engage students often, to enhance their learning. Here are two tips:
    •   When you ask the more complex questions from the lesson, ask students to “turn-and-talk” or “buddy-talk” before answering.

    •   Once you are deep into the lesson, instead of asking students every question provided, ask them to share with you what questions they should be asking themselves at that point in the text. This is also a great opportunity to use "turn-and-talk."
       
  2. Suggested teacher language is included in the lesson.

  3. We recommend you read the book once to your students, either the day or morning before teaching the lesson.

  4. This research-based, read-aloud lesson may seem long. Why do students need the lesson to be this way?
 

Part 1: Teacher Modeling and Questioning

 

Write the following student-friendly learning goal on the board, then read the learning goal out loud with the class:

We will look at the questions asked by a man named Eratosthenes and see how those questions led to a discovery.

 
Prepare Students for the Lesson
 
Show students where Greece, Libya, and Cyrene are on a map. Two maps are provided with this lesson for your convenience.
 
Transition Students into the Text
 
Teacher says: How could a person measure the distance around something as big as the earth? We’re going to read a story about someone who figured out how to do it.
 
Read pages 5 and 6 out loud, then stop. Page 6 ends with, "...couldn't answer." If possible, always show students the illustrations accompanying the pages you read throughout the lesson.
1.
Teacher asks: What words does the author use to describe Eratosthenes as a baby?
 
Students answer: The author uses the words “curious” and “full of wonder” to describe Eratosthenes as a baby.
 
If students struggle with this question, reread the first sentence on page 6: “Even as a baby, Eratosthenes was curious and full of wonder.”
2.
Teacher says: The author gives examples of Eratosthenes’ curiosity. One example is Eratosthenes wondering why there were water droplets on the cistern in the morning. A cistern is a big container for holding liquid.
3.
Teacher asks: What is another example of Eratosthenes’ curiosity?
 
Students answer: Answers may include any of the following.
  • Eratosthenes would crawl across the kitchen to follow ants.
  • Eratosthenes would look at the night sky and wonder why the stars stayed there.
  • Eratosthenes asked lots of questions. (Students may identify specific questions Eratosthenes asked. If so, you may use the opportunity to segue into Steps 7 and 8 below.)
4.
Teacher says: After Eratosthenes learned to talk, he started asking questions. He asked over a thousand of them.
5.
Teacher asks: What are some of the questions Eratosthenes asked?
 
Students answer: Answers should include at least two of the following:
  • How far away is the sun?
  • What is the sun made of?
  • Where do the winds come from?
  • What makes the stars move?
Read more
 
Read pages 9 and 10 out loud, then stop. Page 10 ends with, “...more questions.”
6.
Teacher asks: What was the gymnasium?
 
Students answer:
  • The gymnasium was a school. (acceptable answer)
  • The gymnasium was the school where Eratosthenes went. (strong answer)
7.
Teacher asks: Eratosthenes went to a school called a gymnasium. How did he feel about going there?
 
Students answer: Eratosthenes loved the gymnasium.
8.
Teacher asks: Why did Eratosthenes love the gymnasium?
 
Students answer: Eratosthenes loved the gymnasium because it gave him a chance to ask more questions.
9.
Teacher says (models thinking): This is the second time in the book that we have read about Eratosthenes asking questions. That makes me think questions might be an important part of Eratosthenes' life and an important part of the book. Let’s be on the lookout for more questions as we read.
 
Read pages 12 and 13. Page 13 ends with, “...map of the earth?”
10.
Teacher asks: What new questions has Eratosthenes asked?
 
Students answer:
  • How much of the earth is land?
  • How high is the highest mountain?
  • Is there a map of the earth?
 
If students have trouble remembering all three questions, reread page 13.
 
Read pages 15 and 16 out loud, then stop. Page 16 ends with, “...get around.”
11.
Teacher asks: We knew that Eratosthenes liked to ask questions. Now we learn of something else he liked to do. What was it?
 
Students answer: Eratosthenes liked to make lists.
12.
Teacher says: I wonder whether there are any connections between asking questions and making lists. I can think of one. Someone might ask a question and then make a list of possible answers to it.
13.
Teacher asks: What is another connection between asking questions and making lists?
 
Students answer: Answers may vary.
  • Someone might ask a question and then make a list of steps to find the answer.
  • If someone has a lot of questions, he or she might make a list to keep track of them.
 
Read page 18 out loud, then stop. Page 18 ends with, “...researched here.” Show students Alexandria on a map. You may use the map of the Mediterranean region provided with this lesson.
14.
Teacher asks: What was Alexandria like?
 
Students answer: Responses may vary but should have a basis in the text. For example:
  • Alexandria was the center of all learning.
  • Alexandria had the best library and museum in the world.
  • Big questions about science, literature, and history could be asked and researched in Alexandria.
15.
Teacher asks: How did Eratosthenes feel about being in Alexandria?
 
Students answer: Eratosthenes felt excited.
16.
Teacher asks: Based on what we have read about both Alexandria and Eratosthenes, why was he so excited to be there?
 
Students answer: Alexandria was a great place for him to ask questions and look for answers to them.
 
Read pages 21-23 out loud, then stop. Page 23 ends with, “...musical instrument.”
17.
Teacher asks: What were some of the inventions and discoveries made in Alexandria?
 
Students answer (elicit at least three of the following):
  • The first dictionaries were written there.
  • The first encyclopedias were written there.
  • The connection between a person’s heartbeat and pulse was discovered there.
  • The difference between arteries and veins was discovered there.
  • The first water-driven clock was invented there.
  • The first keyboard musical instrument was invented there.
18.
Teacher says: Besides being a great place to ask questions, Alexandria sounds like a place where a lot of inventions and discoveries were made. That makes me think there might be a connection between asking questions and making discoveries.
 
Read pages 24-26 out loud, then stop. Page 26 ends with, “...questions about the earth—geography.”
19.
Teacher asks: After Eratosthenes became head librarian, what kind of questions began to interest him the most?
 
Students answer: Questions about the earth, or geography, began to interest Eratosthenes the most.
 
Read pages 29-30 out loud, then stop. Page 30 ends with, “...figure it out?” Define “axis” for students on page 30. An axis is an imaginary line around which something turns. The axis of the earth is an imaginary line through the center of the earth, around which the earth turns.
20.
Teacher asks: What are some of the questions Eratosthenes asked about the earth?
 
Students answer: Answers may vary:
  • How far does the earth tilt on its axis?
  • Does the ocean go all the way around the earth?
  • How big around is the earth? (make sure this response is given before moving on)
21.
Teacher asks: What made figuring out how big around the earth is seem impossible?
 
Students answer: Nobody could travel all the way around the earth to measure it.
 
Read page 32 out loud, then stop. Page 32 ends with, “...without it.”
22.
Teacher asks: Eratosthenes began to research, or look for information about, his geography questions. Where was the information he was looking for?
 
Students answer (both of the following responses are acceptable):
  • The information was spread across lots of different scrolls. (make sure this response is given before moving on)
  • The information was not to be found anywhere.
23.
Teacher asks: What did Eratosthenes know he had to do with the facts spread across so many different scrolls?
 
Students answer: Eratosthenes knew he had to bring the facts together in a single scroll.
 
If students respond by saying that Eratosthenes had to write the first geography book, ask what he had to do in order to write that book.
24.
Teacher asks: How might bringing the facts together in one scroll have helped Eratosthenes answer his questions?
 
Students answer: Answers may vary:
  • Bringing the facts together might have helped Eratosthenes compare information.
  • Bringing the facts together might have made it easier for Eratosthenes to see patterns and connections.
25.
Teacher says: Circumference means the distance around something round, like a circle or sphere.
26.
Teacher asks: Eratosthenes wanted to measure the circumference of the earth. What does that mean?
 
Students answer: Eratosthenes wanted to measure the distance around the earth.
27.
Teacher says: We know what Eratosthenes wanted to do at this time in his life. He wanted to answer the question of how big around the earth is in order to complete his geography book. Let’s see whether he is able to answer that question.
 
Read pages 34-38. Page 38 ends with, “...circumference of the earth.”
28.
Teacher asks: How many Alexandria-to-Syene sections would it take to make up the circumference of the earth?
 
Students answer: It would take 50 Alexandria-to-Syene sections.
29.
Teacher asks: Has Eratosthenes measured the distance around the earth? Explain why or why not.
 
Students answer: Students should recognize that Eratosthenes has not measured the distance around the earth. Explanations of “why not” may vary but should reflect the text. So far Eratosthenes has only figured out the angle of the Alexandria-to-Syene section of the earth and how many Alexandria-to-Syene sections it would take to make up the earth’s circumference.
30.
Teacher says: So far Eratosthenes has not measured the distance around the earth. However, he has learned the angle of the Alexandria-to-Syene section of the earth and figured out that it would take 50 of those sections put together to make up the earth’s circumference. Let’s see what he does with this information.
 
Read pages 39-44. Page 44 ends with, “...now complete.”
31.
Teacher asks: What question has Eratosthenes found the answer to?
 
Students answer: Answers may vary but should resemble the following:
  • How big around is the earth?
  • What is the circumference of the earth?
32.
Teacher asks: According to the book, what were the results of Eratosthenes measuring the distance around the earth?
 
Students answer (elicit both of the following):
  • The first accurate map of the world was created.
  • Eratosthenes completed the first geography book of the world.
33.
Teacher says: Earlier in the book, when we read about all the inventions in Alexandria, we wondered whether there was a connection between asking questions and making discoveries. Now think about the question Eratosthenes asked about the distance around the earth. Think about the results of him asking that question.
34.
Teacher asks: Based on Eratosthenes’ experience, is there a connection between asking questions and making discoveries? Explain why or why not.
 
Student response (answers may vary but should all be supported by the book): Yes, there is a connection between asking questions and making discoveries. Eratosthenes’ question led him to discover the distance around the earth and make the first accurate map of the world.
 
Finish reading the book out loud.
35.
Teacher says: Let’s take a close look at one of the last sentences in the book, “…most important of all, he kept asking questions.”
36.
Teacher asks: What are some of the questions Eratosthenes asked during his life?
 
Students answer: Answers may vary but should all come from the book:
  • How big around is the earth?
  • How high is the highest mountain?
  • How far away is the sun?
37.
Teacher asks: Why was asking how big around the earth was important?
 
Students answer: It was important because it led Eratosthenes to measure the distance around the earth.
38.
Teacher asks: Why is knowing the distance around the earth important?
 
Students answer: Answers may vary and include the following:
  • Knowing the distance around the earth helps people make good maps.
  • Knowing the distance around the earth helps people travel.
  • Knowing the distance around the earth can help with transporting goods from one place to another.
39.
Teacher asks: Think again about that sentence, “…most important of all, he kept asking questions.” Why is it so important for people to ask questions? Support your answer with an example from the book.
 
Students answer: Responses may vary, but students should recognize that asking questions leads people to make discoveries. For example, Eratosthenes’ question about the circumference of the earth led to him to figure out a way to measure that circumference.
 

Part 2: Guided Practice and Discussion

 
For this oral lesson, it is suggested to have the completed graphic organizer on the board with the answers concealed before this part of the lesson. After students provide a correct answer, reveal the corresponding answer on the graphic organizer.
 
Transition Students into the Guided Practice
1.
Teacher says: In the first part of the lesson, we looked at many different questions that Eratosthenes asked. Now we are going to organize those questions by group.
2.
Teacher says: Let’s start with the questions that Eratosthenes asked as a little boy, living at home in Cyrene. One question he asked then was, “How far away is the sun?”
3.
Teacher asks: What other questions did Eratosthenes ask as a little boy living at home?
 
Students answer:
  • What is the sun made of?
  • Where do the winds come from?
  • What makes the stars move?
 
All questions asked by Eratosthenes are provided for students at the top of the graphic organizer. The questions are arranged in groups of three. Challenge students to match each group of questions with the correct “Where” category on the graphic organizer as you proceed with the lesson.
4.
Teacher says: When Eratosthenes turned six years old, he went to the gymnasium, or school.
Read more
5.
Teacher asks: Eratosthenes’ favorite subject at school was geography. What questions did he ask his teachers about geography?
 
Students answer:
  • How much of the earth is land?
  • How high is the highest mountain?
  • Is there a map of the earth?
6.
Teacher says: Later in life Eratosthenes moved to Alexandria. He became head librarian of the library there.
7.
Teacher asks: What questions did Eratosthenes ask when he was in Alexandria?
 
Students answer:
  • How far does the earth tilt on its axis?
  • Does the ocean go all the way around the earth?
  • How big around is the earth?
8.
Teacher asks: What were the results of Eratosthenes asking all these questions?
 
Students answer (responses should include at least all of the following):
  • Eratosthenes measured the distance around the earth.
  • Eratosthenes made discoveries.
  • Eratosthenes made the first accurate map of the world.
  • Eratosthenes wrote the first geography book.
 
After the answers for the graphic organizer have been completed and discussed with the class, ask the following two extension questions.
 
Teacher asks: Look over the questions Eratosthenes asked. How are some of them alike?
 
Students answer: Answers may vary and include the following:
  • Many of the questions are about geography.
  • Many of the questions are about things on earth or in the universe.
  • Many of the questions are about nature.
  • Some of the questions are about size.
  • Some of the questions are about distance.
 
Teacher asks: We have seen how asking questions led Eratosthenes to make a discovery. However, he did a lot more than just ask questions to figure out the circumference of the earth. What else did Eratosthenes do that helped him figure out the earth’s circumference?
 
Students answer: Answers may vary and include the following:
  • Eratosthenes gathered information from many different scrolls about math, people, and history.
  • Eratosthenes was creative. He could not measure the circumference of the earth by just walking or sailing around it, so he thought up a way to measure its circumference by using angles.
 

Part 3: Student Independent Practice

 
Both the student question set and teacher answer sheet are provided in the 'Text & Materials' section.

Texts & Materials

Standards Alignment

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