The purpose of this activity is for students to experience the need for a longer length unit and measuring tool. Students practice measuring the lengths of reptiles that are represented by lengths of tape. During the activity, students measure a length of tape that is 1 meter and 80 centimeters long. They can choose to measure with centimeter cubes, 10-centimeter tools, their self-made rulers, or centimeter rulers (MP5). The Synthesis focuses on discussing why measuring longer lengths is difficult with the tools they have. Students consider how longer tools or longer length units would help their measurement challenges. Students measure tape strips A–D in this activity.

• “Which measuring tool did you choose to use? Why?” (We used the 10-centimeter tools and cubes because they were easier to count tens and ones. We used the rulers because we didn’t have to use as many blocks. It was faster.)
• Invite previously identified students to share how they measured the Komodo dragon and calculated its length.
• “What was challenging about measuring longer lengths in centimeters?” (We had to line up our tools and count the centimeters. Centimeters are small so there were a lot of them to count.)
• “Would you want to use these tools to measure real large reptiles?” (No. It would take too long. I might get bit.)
• “What would make measuring longer lengths easier?” (We could use a tool that has more centimeters on it. We could use a longer length unit to measure.)

The purpose of this activity is for students to learn about the meter as a longer metric unit of length. Students measure longer lengths with a new tool, the meter stick. Students measure strips of tape of different lengths and choose between a centimeter ruler and a meter stick in order to measure each. In the Synthesis, students share their measurements of each line and discuss how they chose which tool to use to measure (MP5). Students measure Strips D–G in this activity. Students measure the Komodo dragon (Strip D) twice to experience measuring the same length with a ruler and a meter stick. They discuss and compare their measurements in the Lesson Synthesis.

• “Which tools did you use to measure Strip G, the ribbon snake? Why did you choose this tool?” (We used the meter stick and took away 10, because it was so close.)
• “What did you do when you found that Strip E, the adult alligator, was longer than 3 meters but shorter than 4 meters?” (We saw it was closer to 3 meters so we said it was about 3 meters. We used the meter stick 3 times and then the cm ruler for the rest.)