# Pi Day Festival Lesson Plan: Exploring Circumference and Diameter

In this Pi Day lesson plan, which is adaptable for grades 6-12, students use BrainPOP resources to explore the relationship between circumference and diameter in order to calculate pi. Students will complete a variety of fun hands-on activities as they describe the differences between theoretical pi and realistic calculations of pi in a celebration of Pi Day.

### Students will:

- Explain the relationship between circumference and diameter in order to calculate pi
- Describe the differences between theoretical pi and realistic calculations of pi

### Materials:

- List of pi digits print out from BrainPOP's "Comic" section
- 1 fork per student
- 25-30 circular objects to be measured for pi calculations
- String
- Scissors
- Rulers
- Calculators
- Scrap paper
- Pencils
- Laws & Customs print out from BrainPOP
- Access to BrainPOP and projector

### Vocabulary:

pi, circumference, diameter, irrational number, rational number

### Preparation:

Start talking about Pi Day well in advance to build excitement! Start a sign-up list for Pi Day events prior to the week of National Pi Day (check the official Pi Day website for this year's date). Previous completion of a unit on circles is very helpful but not required. Decide as a class how you will grade the Pi Bake Off (creating a rubric as a class works great.) Pre-assign groups of 2-3.### Lesson Procedure:

**EXPLORATIONS**

a) Watch the BrainPOP Pi video explaining the concept of Pi.

b) Give each group several objects that are cylindrical in shape. Project the BrainPOP Experiment for students to see. Have each group complete the activity on several objects.

c) As a class, compare calculations to see which object came closest to being a perfect circle.**BEGIN COMPETITIONS:**

Set the room up like a performance. Each “show” will involve a different cast of students who signed up to participate. Begin in any order. If you don’t have enough time to highlight each student, set your classroom up like a fair in which each corner of the room has a different activity taking place, and students can roam and observe.- Be sure everyone gets to see the Pi Bake Off entries before you dig in! Display the art before class starts. Delegate “judges” to rule a winner in the Pi Memorization competition. Be sure everyone gets a chance to vote anonymously for the art, Pi-philologist, and bake off competitions. Don’t let students calculate the winners.
**Pi MEMORIZATION CONTEST:**

Have students spend their own time memorizing as many digits of pi as they possibly can! Give each students a copy of the Dates & Times to share many of Pi’s digits.- During class, each student will recite as many Pi digits as they possibly can!
**Pi ART COMPETITION:**

Students may create any form of art they see fit that exemplifies the meaning of pi. I’ve seen graphic art, paintings, photographs of nature, sculptures, you name it. Each submission has to express the relationship of circumference to diameter. An early submission could be a poster advertising Pi Day!**Pi BAKE OFF:**

Have students bake their own homemade treats in circular forms. They should decorate each entry to promote Pi and its significance.- Have the class create a scoring rubric to grade each entry. Be sure to distinguish the difference between PIE and PI, a cookie, cheesecake, etc. All are acceptable as long as they are circular and one could potentially compare the circumference and diameter to theoretical Pi. Students enjoy this one the most. Each student samples the entries and uses the rubric to assign scores.
**PIPHILOLOGIST:**

Print the piphilologist information for anyone who is interested. This contest’s winner will be decided by a class vote. Each mnemonic device will be submitted typed and nameless for voters to remain unbiased.**CLOSING ACTIVITIES:**

Play BrainPOP’s Q&A section of Pi as a game. Use the same groups that started the class off.- Take the BrainPOP Review Quiz for Pi. This version makes sure you get the right answer before you move on, which is a great time saver when you are approaching the end of class!
**EXPLORATIONS:**

Begin by watching the BrainPOP Pi video explaining the concept of Pi.- Give each group several objects that are cylindrical in shape. Project the Experiment for students to see. Have each group complete the activity on several objects.

### Extension Activity:

For homework, have each student complete the Do It questions in the FYI section. Also hand out the Laws & Customs story for each student to read. Each student should write at least one paragraph (3-5 complete sentences) analyzing the story. They can discuss any of the topics below, or anything that they feel is appropriate to the topic:a) What would have happened if Pi had been changed to 3.2?

b) Should congress have the ability to approve mathematical proofs?

c) How is 3.2 different from Pi?