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Perimeter, Area, and Circumference
Measuring Radius, Diameter, and Circumference

Overview of Lesson: In this lesson, the students will listen to the stories, Sir Cumference and the First Round Table and Sir Cumference and the Dragon of Pi, by Cindy Neuschwander. These stories give a vivid explanation of radius, diameter, circumference, and pi. After listening to the story the students will set out to find the radius, diameter, and circumference of various circle objects around the room as well as ones that they have brought from home. They will record the data that their group collects on individual sheets that have columns for all three measurements.

Standards:

Mathematics:

(See Standards Link for Complete Standards)

Number Sense and Operations- 6.N.13

Measurement- 6.M.1, 6.M.5

Student Outcomes: By the end of the lesson, the students will be familiar with the terms radius, diameter, and circumference. The students will also be able to measure the radius, diameter, and circumference of circles using a piece of string and a ruler.

Lesson 5 of 9

Length of Lesson: 45 Minutes

Instructional Mode: Whole Class/Small Group

Multiple Intelligences: Verbal-Linguistic, Logical-Mathematical, Bodily-Kinesthetic, Interpersonal

Essential Questions:

What are diameter, radius, and circumference?

How do you find the circumference of a circle using a piece of string and a ruler?

How are radius and diameter related?

Materials/Resources Needed:

1. Sir Cumference and the First Round Table, by Cindy Neuschwander

2. Sir Cumference and the Dragon of Pi, by Cindy Neuschwander

3. Various circular objects

4. String

                    5. Rulers

                    6. Worksheets for Recording Data

Instructional Strategies/Procedure:

    1. Teacher will read Sir Cumference and the First Round Table and Sir Cumference and the Dragon of Pi aloud to the students to give them some background information and explanations of radius, diameter, circumference, and pi.
    2. Throughout and after the stories, a short discussion should occur to be sure that the students understand the above mentioned concepts.
    3. Pass out the chart sheets so that the students will be able to record their data.
    4. Pass out string, rulers, and circular objects. It is best to have the students work in pairs or small groups to conserve on supplies as well as to help one another.
    5. Explain to the students that they will be measuring the radius, diameter, and circumference of each of the various circles. The diameter will be measured with the ruler across the circle through the center. It is important to stress to the students that the diameter needs to cross the center of the circle because it is the longest distance across a circle. Radius is exactly half of the diameter.
    6. Once all the directions have been given and all questions have been answered, the students will measure the circumference of the circle by wrapping a string around the outside edge of the circle and either marking the string. Then they will stretch out the string straight and measure it to the mark with their ruler. They will also measure the radius and diameter of the circles. (Some students will realize that if you measure the diameter, they don't need to measure the radius because the radius is half of the diameter. This is great!)
    7. The students will record all of their data on their sheets to use in the next lesson. It is crucial that the students measurements are as accurate as possible.

Assessment: By watching and observing the students as they measure their circles' diameters, radii, and circumferences, the teacher will be able to see if the students truly understand what diameter and circumference are. The discussion after the read alouds will also allow the teacher to see if students are grasping the major concepts.

Evidence that Student Learning Occurred: The students should be able to successfully complete the worksheet if they understood the concepts of radius, diameter, and circumference from the stories. The students who make the connection between radius and diameter and understand that they do no have to measure the radius if they know the diameter or vice versa, truly understand those measurements.

Technology Skills Required or Developed: There are no technology skills required for this particular lesson.

Resources:

Neuschwander, C. (1997). Sir Cumference and the Knights of the Round Table. New York: Scholastic Inc.

Neuschwander, C. (2000). Sir Cumference and the Dragon of Pi. New York: Scholastic Inc.

Measuring Radius, Diameter, and Circumference Worksheet

Student Work- Measuring Radius, Diameter, and Circumference