Length Measurement in Grade 1 Blueprint

[teachtucson]

I am a curriculum designer who specializes in aiding teachers in designing curriculum maps and curriculum units. I have been using the progressions extensively. In the K–5 Geometric Measurement (page 9, paragraphs 3 & 4) states regarding manipulative standards units:

“Another important issue concerns the use of standard or nonstandard units of length. Many curricula or other instructional guides advise a sequence of instruction in which students compare lengths, measure with nonstandard units (e.g., paper clips), incorporate the use of manipulative standard units (e.g., inch cubes), and measure
with a ruler. This approach is probably intended to help students see the need for standardization. However, the use of a variety of different length units,
before students understand the concepts, procedures, and usefulness of measurement, may actually deter students’ development. Instead, students might learn to measure correctly with standard units, and even learn to use rulers, before they can
successfully use nonstandard units and understand relationships between different units of measurement. To realize that arbitrary (and especially mixed-size) units result in the same length being described by different numbers, a student must reconcile the varying lengths and numbers of arbitrary units. Emphasizing nonstandard
units too early may defeat the purpose it is intended to achieve. Early use of many nonstandard units may actually interfere with students’ development of basic measurement concepts required to understand the need for standard units. In contrast, using manipulative standard units, or even standard rulers, is less demanding and
appears to be a more interesting and meaningful real-world activity for young students.
Thus, an instructional progression based on this finding would start by ensuring that students can perform direct comparisons.Then, children should engage in experiences that allow them to connect number to length, using manipulative units that have a standard unit of length, such as centimeter cubes. These can be labeled “length-units” with the students. Students learn to lay such physical units end-to-end and count them to measure a length. They compare the results of measuring to direct and indirect comparisons.”

After much deliberation regarding the above progressions paragraphs, as well as related paragraphs for Grade 1, and Grade 2’s mention (page 12, paragraph 1) of: Measure and estimate lengths in standard units: Second graders learn to measure length with a variety of tools, such as rulers, meter sticks, and measuring tapes (2.MD.1 – Measure the length of an object by selecting and using appropriate tools such as rulers, yardsticks, meter sticks, and measuring tapes.), teachers I have been working with purposefully have Grade 1 students exploring/learning length measurement concepts with MANIPULATIVE standard units only. We agree it makes sense maturationally/ cognitively since the manipulative units used in Grade 1 are in actuality standard (e.g., button that is 1 cm, tile that is 1 in., dowel that is 1 ft., string that is 1 m), so that when the students begin Grade 2 the transition to a standard unit length (2.MD.A.3 …inches, feet, centimeters, meters) using rulers, yardsticks, meter sticks, and measuring tapes will be a natural and smooth transition.

So, what is my specific question? Why does the newly published Grade 1 blueprint have a unit that encourages a transition to using a ruler in Grade 1 based on what the progressions encourage regarding manipulative units as well as Grade 2’s expectation for using a standard tool: ruler, yardstick, etc.?
Unit 1.1 “Length and the Number Line” states:
Students begin their work with standard units as well. A good transitional activity would be using a 12-inch ruler to measure the side-lengths of a train of 1-inch tiles; this makes the connection between iterating length units (the tiles) and the structure of the ruler clearer.
We have the “transitional activity” in early on in Grade 2, not Grade 1 based on the progression’s recommendations.

Thank you in advance for your response.

P.S. Could you please include an “updated date” when making any changes to the progressions? I have noticed nuance modifications and additions to some of the progressions over time, but the draft date does not get updated (e.g., Draft, 6/23/2012). Thank you!

[Bill McCallum]

Thanks for pointing this out … I’m going to pass it on the blueprint authors for comment. And yes, I try to include the update date, but sometimes I forget!

[Author]

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