“In kindergarten, students will vary quite a bit in how accurately and consistently they compare the length of things. The “mistakes” are not carelessness or sloppiness; instead, these students are still figuring out what it means to measure length, and how to go about it.” Marilyn Burns
Rather than simply telling students to align the ends of two object carefully in order to compare, we encourage discussion among the students about the different ways they are measuring.
“This foot is longer than my arm!” (She was using a paper cut-out of a foot). When observing the student, I could see that the ‘foot’ was placed in middle of the arm. I asked her about her own foot, and if she thought her foot was longer than her arm. This led to a discussion of arms and feet. The student then compared her foot to her forearm and noticed that the length from wrists to elbow was almost the same. So, I tried it. And guess what? She was right!
As a class, we used our construction paper “feet” to compare lengths with various items in the classroom. They recorded the results through drawings for what was longer than and what was shorter than.
“Research on children’s mathematical understanding shows that students typically do not develop a firm idea about length as a stable, measurable dimension until toward the end of the primary grades, although, as we know, there is a range of individual differences among students. Yet, as students discuss and compare ways of measuring, they will gradually develop a sense of what length is and how to measure it accurately. ” Meghan Murray
We will continue to explore length and measurement using non-standard units of measurements (cubes, blocks, hands, feet).