Beacon Lesson Plan Library

How Long Is Your Smile?

Kachanda Silva


This activity is a creative way for students to learn to measure to the nearest centimeter. Students will work together to create a portrait of themselves with an accurate measurement of their smile to the nearest centimeter.


The student solves real-world problems involving measurement of the following: length (for example, millimeter, quarter-inch, foot, yard, meter); weight (for example, pounds, ounces, kilograms, grams); capacity (for example, cup, milliliters); temperature (Farenheit and Celsius); angles (right and straight).


-Crayons, colored pencils, or markers
-Overhead projector
-Overhead ruler


1. Create a chart with steps 14-19 so that students can refer to it during the lesson.
2. Cut enough pieces of string for each student in your class. The strings should be at least 10cm long.
3. Copy the two attached sheets for each student.
4. Create an overhead transparency of the How Big Is Your Smile? practice sheet.


1. Begin by having the students examine a ruler on the centimeter side.

2. Explain that today they will work with the centimeter side of the ruler only.

3. Using the overhead and an overhead ruler, show students how to line up an object to the ruler correctly.

4. Distribute the practice sheet and a scrap piece of paper.

5. Model measuring several objects to the nearest centimeter on the overhead.

6. On the scrap sheet have the students practice drawing lines to the nearest centimeter. For example, have the students draw a line that is three centimeters long. Walk around to observe and help students who need assistance.

7. Through observation, observe when most students understand how to use the ruler to measure to the nearest centimeter. Next, have the students measure the smiles on their practice sheets to the nearest centimeter.

8. After the students measure the smiles on the paper, ask them how they think I could measure an object that is not straight or flat. (Accept all responses.)

9. Put up an overhead of the How big is your smile? sheet, and review the answers together as a class. Have the students correct their own papers using a red colored pencil. Walk around, taking note of which students need extra instruction.

10. Explain that today they will be measuring their own smiles. Ask for suggestions on how they could do this accurately.

11. Distribute a piece of string and scissors to each child.

12. Have the students sit face to face with their partners.

13. Demonstrate the steps 14–19 using yourself and a student to model the process before the students begin. Create a chart with steps 14-19 on the board or overhead so that students may refer to the chart if they forget a step. Before the students begin the activity, review the cooperative learning rules for your classroom.

14. Provide these instructions to students:

Show your partner your biggest closed mouth smile.

Place one end of your string in the corner of your smile and loosely lay the string across the full length of your smile. While you hold the string at your smile’s endpoints, have your partner cut the string for you. Be sure to take the string away from your mouth before cutting.

Lay the string out flat on your desk, and then use the centimeter side of your ruler to measure your string to the nearest centimeter.

After measuring and recording your findings, have your partner measure your string to see if he/she got the same answer.

If answers vary, call a teacher over for help.

Using the head pattern create a portrait of yourself. Glue the string down as your smile.

Save this self-portrait. It will be used in a later literature lesson.


Note: This lesson assesses measuring length to the nearest centimeters.

*The teacher will observe the students during the lesson to see if they understand how to measure to the nearest centimeter. They can also view the centimeter practice sheet used during the lesson. Students should have at least three out of four correct answers.

* Teacher will also observe to see if students are following the classroom cooperative learning procedures.


As an extension activity, the students can create an autobiographical poem to go along with their self-portrait. The format for the poem is as follows:
Line 1: First Name
Line 2: Was born in ________ (list city and state of birth)
Line 3: Has ________ siblings (fill in with number of brothers and sisters)
Line 4: Likes to… (list at least three things that you like to do)
Line 5: Is afraid of … (list at least one thing you are afraid of)
Line 6: Loves __________ the most in school (fill in with your best subject)
Line 7: Last Name

Attached Files

Practice Sheet and Portrait Template     File Extension:  pdf
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