Beacon Lesson Plan Library

Measure This!

Kim Auerbach


Students estimate in centimeters the measurement of ten items that are in a paper bag and record the results. Sudents then measure the items using a centimeter ruler and record the results next to the estimates.


The student estimates the measure (length, weight or mass, and capacity) of an object or figure and then compares the estimate with the actual measurement of the object or figure.


- Paper lunch bag containing one of each of the following items:
-Licorice stick
-Miniature wrapped candies
-Twist tie (from garbage bags)
-Plastic spoon
-Large paper clip
-Index card
-Centimeter ruler
-Activity sheet to record results (see Associated File)


1. Prepare bag with items.
2. Premeasure all items to ensure students are close in actual measurements.
3. Copy activity sheet. (See Attached File.)
4. Gather centimeter rulers.


1. Students should have prior knowledge of measuring with a centimeter ruler and finding the absolute value of a number.

2. Give students a paperbag that contains ten items and an activity sheet. The bag should be stapled closed.

3. Tell students: Today you are going to estimate the length of 10 common objects. Why is it important to know how to estimate? (Discuss with the class.) Then continue: First, you are going to practice using your tactile skills. Unstaple your bag carefully, but don't look inside. Place your hand inside the bag, and choose one object, but don't take it out! By touch only, see if you can guess what the item is. (Call on several students to give an oral description of their items, and see if other classmates can correctly guess the item.)

4. Continuing, students are to pull out one object at a time, recording the type of object on the activity sheet.

5. Examine the object and estimate the length to the nearest tenth of a centimeter.

6. Record estimates of all ten items on the activity sheet.

7. When they have finished estimating, students should raise a hand to obtain a centimeter ruler.

8. Model how to accurately measure to the nearest tenth of a centimeter and then allow students time to record all measurements on the activity sheet.

9. Model how to find the difference between the estimate and the actual measurement of the object. Then allow time for students to find the difference between the estimate and the actual measure. Record the absolute value of the difference on the activity sheet.

10. Total the absolute values.

11. Discuss the total differences within the classroom, most accurate (smallest decimal difference) to least accurate (largest decimal difference).

12. Students write a paragraph summarizing the activity. It should include the self-evaluation of their estimation skills based on the activity. (For example: Do they think they are accurate enough, or do they need more practice?) The paragraph should also include any techniques or strategies they discovered to help them estimate more accurately.


Assessment is based on completed worksheet:
Estimates of all objects in the bag-1 point
Actual Measurements of all objects in the bag-1 point
Differences between estimates and actual measurements are calculated-1 point
Paragraph that explains the strategy they used to estimate and how close to the actual measurements were to their estimates-1 point

Since this is a formative assignment, use the following scale for determining who needs feedback and additional practice:
4 points = SUPER JOB
3 or less points = See me and let's figure out what you need to do to earn the rest of the points.


Students re-measure items using a non-standard measurement system. (How many lengths of paperclips, twist ties, etc., is each item?)

Attached Files

A table to record items and measurements.     File Extension: pdf

Return to the Beacon Lesson Plan Library.