Image of the Week: Estimating Length

Estimating Length

One of our most popular Off You Go activities invites students to hunt for objects that are about 10 cm long to build an understanding of this linear measurement. These kinds of activities build deep embodied understandings of units of measure that students can then use to estimate lengths in the future, just as number benchmarks help students estimate quantity. For students to really know how to use units of measure, they need a deeply held sense of each unit and how it relates to their world and, in the case of lengths like 10 cm, their bodies. When someone says, “10 centimeters” we want students to feel their fingers moving apart just that distance, knowing how 10 centimeters relates to the size of their hands and arms. To develop this understanding, they need lots of opportunities to physically interact with objects and their measurements. So, share this image with students and then send them off to find object that they feel are about 10 centimeters long. This is particularly hard and important work for those of us not used to metric units; the reason it is hard is that we don’t have these units held in our bodies, so we need experiences to learn what they feel like.

Some students might resist the idea that we can hold mathematical ideas in our bodies, but this is at the heart of learning and doing mathematics. From an early age, we count on fingers, we manipulate figures and puzzle pieces, we navigate three-dimensional space physically, and we embody concepts like symmetry. When looking for objects that measure about 10 centimeters, encourage students to only start with their eyes and then quickly move to their hands to feel what that distance is like compared to their bodies.

And if you want to explore other lengths or units, don’t fret! We have Off You Go activities to look for objects that measure about 1 inch, 3 inches, 6 inches, 1 foot, and 1 centimeter.

To multiplicity, cheers!

Jen Munson and the multiplicity lab group