Fisherman's Journal: Understanding Measurement

7 teachers like this lesson
Print Lesson


SWBAT create guidelines for how to measure length.

Big Idea

Students explain how to measure fish in this rigorous introduction to measuring length!


5 minutes

Opening Discussion

15 minutes

I’ll give my students the background they need for fishing to start the lesson. Many of my urban students do not know much about fishing at all! The main thing they need to know is that a fish must be a certain length to keep it, in this case 6 tiles long. We call these fish "keepers".

I’ll show the students three fish in this order. The fish are attached and numbered! I also attached a picture of the anchor chart my class and I made.

After each fish, we will do some questions and write down the mistakes our principal made.


Attached Fish 1: “Let me show you the first way he measured. (Show attached picture 1 and post it). I said it was 6 tiles long. I want you to take a second and decide if you think he’s right. Give me a silent thumbs up or down when you think you know. “


Attached Fish 2: “OK. Well I measured it again. And this time (Attached picture), he figured out it was 8 tiles long! “That’s strange,” he thought. I got 2 different n umbers. “

  • Why did he get 2 different numbers? Did he measure it correctly?


Attached Fish 3: “Now my friend was really getting mad. He decided to give it one more try. This time he did it this way: He counted-1, 2, 3, 4. He thinks it is 4 tiles long but I’m not sure.

  • What do you think?” Show thumbs up or down.”
  • What is wrong with the way I measured this fish? (I’ll record what they write down with the attached picture).


After fish questions:

  • If you were to measure this fish, where would you have to put the first tile? 
  • Where would you line it up? Where would the tiles have to stop? 
  • Why couldn’t you just put another one at the end? 
  • Where could I draw a line that shows me where to start? How about a line that says where to end?


Partner talk for review: What mistakes did my friend make when he measured the fish?



Student Share

15 minutes

Our thinking job today is: What rules do I need to follow to measure the length of an object using inch tiles? With a partner, you are going to show me how we can follow these rules to measure the fish the right way.


I'll have students measure the fish in partners with inch tiles. After students measure, we will come back together and I’ll have one student show how he/she measured it.


“I’ll narrate as student measures: You are lining your tile up with the end, you are keeping your tile’s straight, you are making sure there are no gaps, and you are going until you reach the other end of the fish. “


Partner Talk: Everyone got 7 this time! Can you tell your partner what rules did we have to follow to make sure we measured our fish correctly?


Let’s go back to our original dilemma-we were trying to figure out if this fish is a keeper or not. A perch has to be at least 6 inch tiles long-was the perch longer or shorter than 6? Show me with your hands. Yep! 7 is more than 6 so this fish is a keeper!

Independent Practice

15 minutes

Students get a "Fisherman's Journal" with fish on it to measure with inch tiles. Students write how long each fish is. 

Extension: After measuring all of the fish, students identify which fish are keepers (at least 6 inch tiles long). Common Core pushes writing across the curriculum, so students also write an explanation for how they know those fish are keepers. 

**See attached video of a student working.**

Closing and Extension

5 minutes