How Big Are You?

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The students will be able to measure lengths of their body and convert these measurements within the same system of measurement in a real-world context.

Big Idea

Students love math related to themselves. This lesson provides rich opportunities to practice fraction skills while converting from inches to feet and inches, and calculating mean, median, mode, range, and outliers.


This lesson focuses on real life measurement where students are going to be measuring, in inches, the length and/or circumference of arms, legs, head and torso.  It is a great activity to save in a portfolio and give back at the end of the year.  Because I teach students in a multiage setting I save a copy of the activity for them and include it in a portfolio my students take home at the end of their 5th grade year. 






Exploration of Measurement

30 minutes

This is an active lesson where students need to be prepared to be up and moving around successfully in the classroom.  They will be measuring five different body lengths on a partner and comparing it to their own measurements.  I start the lesson modeling with a student partner explaining also how to measure to 1/4 of an inch.  This lesson comes after I have had the students make an enlarged version of a inch divided into eights.   It will take two math periods - one for the measurement data collection and one for the mean, median, mode range and outliers.

I open this lesson modeling how to measure each body length on the handout and reviewed how to measure to a 1/4 inch - activating previous knowledge.  

To quickly put the students into pairs I drew sticks with their names on them. I find students more willing to work with a partner when the pairing is random and they know it is only for a short period of time. I've established from the start that every student will be working with everyone else in the class at some point every month.  

Students gather their materials - a measuring tape and the handout - and spread throughout the room.  I typically cut yarn for each pair of students and give them a yard stick but this year I found measuring tapes buried in my math manipulatives.  This was so much easier than the yarn, but if you don't have tapes the yarn will work. 

Because one of the measurements is around the neck, I recommend that students do this measurement on themselves. I model how this is done - and keep an eye and ear towards my more active students.  I also model where to measure from the shoulder and hip bone and how to stand against a wall or flat surface, place a hand on the persons head and fingers against the wall to mark the height.  Otherwise some students will be uncomfortable or just do silly measuring of another person's height.  I ask students why they would get a more accurate measurement from the flat wall than the bumpy person. We have really been working on being mature and my expectation is that we have a mature discussion.  I am pleasantly surprised when my students meet that expectation.  

Students Working Together

Once all of the measurements are completed in inches, I ask students to convert to feet and inches.  (5.MD.A.1)  Some students struggle to do this since I had not directly taught it.  This isn't an oversight. I want students to use their thinking skills and reason it out by themselves. I find the more I ask students to do without my help, the more skilled they become at finding the answer.  

At one point a student realizes that 12 inches to a foot is equivalent to thinking in multiples of 12.  This is an "Ah Ha moment", and I stop everyone so the student can share. The measuring tape only indicates a foot with a tiny star at each 12 inch interval.  Building on this student's discovery, I suggest students count the number of stars and apply thinking about multiples of 12.

We have a meeting and the speaker tells us math is not a bunch of disparate ideas, added on top of each other.  Math is a collection of connections.  The more you know about math the more you see these connections.  This has really stuck with me and I am making more connections within math.

Earlier in the year I incorporated measurement in other lessons (see Multiplication Array for one example) before direct instruction in measurement.  I believe the lesson today went very smoothly because of all the previous exposure to measurement.  

Another important context for this lesson arises from slippage in student behavior; my students, despite explicit modeling and practice in social/academic interactions, have begun using put-downs and struggling to work together. So today I integrate collaboration strategies into the lesson.  I open this lesson with students in a community circle considering the question, "What would you like to hear another person say when you make a mistake?"  I had set this up earlier when I told a student they had a wrong answer on their morning math wake up activity, and then publicly apologized to the student.

The majority of the students share that they'd like others to politely tell them they made a mistake, and for the student who expressed their thinking in a way that hurts, to be able to apologize or have the chance to correct this mistake.