Can You Measure It?

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Objective

SWBAT identify at least 3 types of measurement and use these to solve problems.

Big Idea

Measurement is one of the 4 Critical Areas in 2nd Grade Math. At the start of the year, students are exposed to a variety of ideas about what math really is. Measurement is one important areas of math that students don't often think of.

Getting Started

15 minutes

Students will start today by counting by twos from both odd and even numbers. Students are familiar with counting by 2s from even numbers, but the odd numbers are more difficult.

I begin by having students take out their journals and record counts by 2 from 10 - 30. After reviewing these I ask students, "What would happen if we start counting by 2s beginning at 11?" I let students record their thoughts and attempts in their journals and then I ask them what they noticed? I've found students often count to the next even number, say in this case 11, 12, 14, 16 or revert to counting by ones so I will circulate around as students are recording and note who is having difficulty.

I discuss with students how counting by 2s from 11 is harder, but still follows a pattern. I ask them to circle the digit in the ones place for all their counts. We review where the ones place is in a number (its always the last one in the line.. the little one). I ask students to see if they see a pattern in the ones place (1, 3, 5, 7, 9). I take their ideas and we discuss each one, eventually reaching the odd number pattern.

Patterns are an important part of math and so I have chosen to start with patterns today. I know that as students work through the measurement part of this lesson, they may not see why I started with number patterns, but often the warm up is a time for a quick review to keep students thinking about more than one aspect of math at a time. 

I give students a quick stretch break and ask them come to the circle where I have a bottle of water, a bucket of rocks  and a large rock. I ask students, "How we might measure these items?"

Students make suggestions and I record their ideas without any feedback. Next, we analyze the practicality of the suggestions (i.e. I asked for a student to show me how they might measure the rocks or water with a ruler and what kind of result we are getting - how tall the water in the bottle is or about how long a rock is.) I want students to critique the suggestions and see if the suggestions make sense (Common Core MP3). 

We agree on certain ways we might measure the objects, but up through this discussion students could not see the measuring tools I had ready to introduce in our next discussion.  I wanted to see what measuring tools they were familiar with and might suggest. I am also looking to see if they can choose the correct tools for the job (MP5) so  after the discussion I show a scale, a measuring cup, and a yardstick and tape measure.

After we've determined measurements, we discuss what these numbers mean (e.g., they need a unit of measure). The unit of measure is important here. I want to introduce students to the fact that when I measure each thing I need to specify the unit. I say, "If I am measuring how heavy I am, would I say, I weigh 80 inches?" "What if I wanted to know how tall you are and I measured you, would it be ok to say you are 50 pounds tall? Why not?" I let students volunteer their ideas for why this wouldn't work here. 

I tell students that they will have the opportunity to measure today and they will record what they measure, how big it is, and the unit of measure. They will be working in partners or small groups for this activity.

Before moving to the small group activity, I proactively manage potential behaviors by having a brief discussion with interactive modeling of what it means to work with a partner or small group. We discuss sharing, being kind, taking turns and listening to one another.  I count students off by 4s and send each group to measure the objects in their center.

Practice

40 minutes

There are 4 centers for students to pass through. I find it easiest to assign each group to a starting center, to set the timer for 10 minutes and to then have the groups record what they have done, clean up and rotate to the next center.

The four centers are (1) measuring liquid with measuring cups and spoons, (2) measuring linear objects in the room using rulers, yardsticks, and tape measures, (3) measuring the weight of books using a scale, and (4) an area to build with base ten blocks for 30 seconds and then count the number of square units (volume) that are in their buildings.

I have included the measuring with liquid, linear measures, weight and volume in this lesson to reinforce the importance of recording the unit of measure. Students should not record each answer as inches. Developmentally Appropriate Practices in Measurement

Directions for each center are posted to remind students what they need to be doing. I use parent volunteers when possible to assist with the centers. I have an introductory session with parents before they volunteer. I talk about encouraging students to think for themselves by asking how and why questions. I ask parents to support student work by providing hints if needed, but not giving students answers. I also remind parents to praise student work specifically such as, you have done a good job remembering to write the unit of measure here. 

Closing Circle

10 minutes

After the last center is cleaned up I bring students back to the circle to discuss what they found out. I let students refer to their journals to tell what they found and to make it possible to compare measurements. We recorded some of the measurements to reinforce the idea that things can be measured in more than just inches.

After the lesson, I collect student journals to look at the measurements they recorded. I am looking for logical measurement numbers and for a unit of measurement for each answer. I know that students did not do all of this work independently, but by looking at their journals I have a sense of which students are still struggling with using a measuring tool correctly (MP5), which students are able to be precise in their measurements (MP6), and which students understand the idea of units of measure. (I also watched as students visited centers to gain additional input on these goals.) This is an early measurement lesson for the year so I do not expect total proficiency with measurement at this time.