Meters and Centimeters
10 min
Narrative
The purpose of this Warm-up is to elicit what students know about length measurement and about units of measurement. While no unit is specified for the ruler in the image, students are likely to bring up centimeters (given the way each 1 unit is partitioned into 10 smaller parts, as seen on centimeter rulers). The work here prepares students to think about the relationship between meters and centimeters later in the lesson.
Launch
- Groups of 2
- Display the image.
- “What do you notice? What do you wonder?”
- 1 minute: quiet think time
Teacher Instructions
- “Discuss your thinking with your partner.”
- 1 minute: partner discussion
- Share and record responses.
Student Task
What do you notice? What do you wonder?
Sample Response
Students may notice:
- The little bug is 1 unit long.
- The long bug is more than 12 units long.
- The ruler shows 12 units.
- Does the ruler show centimeters or another unit?
- What bugs are these?
- How long is the big bug?
Activity Synthesis (Teacher Notes)
- Consider sharing that the large insect is a stick insect. (The longest species of stick insect ever found measured more than 60 cm.) The small insect is a green potato bug.
- “If each unit in the ruler is 1 centimeter, about how long is the potato bug?” (1 cm) “What about the stick insect?” (About 16 cm with the antennae, about 12 cm otherwise.)
Standards
Building On
- 2.MD.1·Measure the length of an object by selecting and using appropriate tools such as rulers, yardsticks, meter sticks, and measuring tapes.
- 2.MD.A.1·Measure the length of an object by selecting and using appropriate tools such as rulers, yardsticks, meter sticks, and measuring tapes.
Building Toward
- 4.MD.1·Know relative sizes of measurement units within one system of units including km, m, cm; kg, g; lb, oz.; l, ml; hr, min, sec. Within a single system of measurement, express measurements in a larger unit in terms of a smaller unit. Record measurement equivalents in a two column table. <em>For example, know that 1 ft is 12 times as long as 1 in. Express the length of a 4 ft snake as 48 in. Generate a conversion table for feet and inches listing the number pairs (1, 12), (2, 24), (3, 36), …</em>
- 4.MD.A.1·Know relative sizes of measurement units within one system of units including km, m, cm; kg, g; lb, oz.; l, ml; hr, min, sec. Within a single system of measurement, express measurements in a larger unit in terms of a smaller unit. Record measurement equivalents in a two-column table. <span>For example, know that 1 ft is 12 times as long as 1 in. Express the length of a 4 ft snake as 48 in. Generate a conversion table for feet and inches listing the number pairs <span class="math">\((1, 12)\)</span>, <span class="math">\((2, 24)\)</span>, <span class="math">\((3, 36)\)</span>, …</span>
25 min
10 min
Knowledge Components
All skills for this lesson
No KCs tagged for this lesson
Meters and Centimeters
10 min
Narrative
The purpose of this Warm-up is to elicit what students know about length measurement and about units of measurement. While no unit is specified for the ruler in the image, students are likely to bring up centimeters (given the way each 1 unit is partitioned into 10 smaller parts, as seen on centimeter rulers). The work here prepares students to think about the relationship between meters and centimeters later in the lesson.
Launch
- Groups of 2
- Display the image.
- “What do you notice? What do you wonder?”
- 1 minute: quiet think time
Teacher Instructions
- “Discuss your thinking with your partner.”
- 1 minute: partner discussion
- Share and record responses.
Student Task
What do you notice? What do you wonder?
Sample Response
Students may notice:
- The little bug is 1 unit long.
- The long bug is more than 12 units long.
- The ruler shows 12 units.
- Does the ruler show centimeters or another unit?
- What bugs are these?
- How long is the big bug?
Activity Synthesis (Teacher Notes)
- Consider sharing that the large insect is a stick insect. (The longest species of stick insect ever found measured more than 60 cm.) The small insect is a green potato bug.
- “If each unit in the ruler is 1 centimeter, about how long is the potato bug?” (1 cm) “What about the stick insect?” (About 16 cm with the antennae, about 12 cm otherwise.)
Standards
Building On
- 2.MD.1·Measure the length of an object by selecting and using appropriate tools such as rulers, yardsticks, meter sticks, and measuring tapes.
- 2.MD.A.1·Measure the length of an object by selecting and using appropriate tools such as rulers, yardsticks, meter sticks, and measuring tapes.
Building Toward
- 4.MD.1·Know relative sizes of measurement units within one system of units including km, m, cm; kg, g; lb, oz.; l, ml; hr, min, sec. Within a single system of measurement, express measurements in a larger unit in terms of a smaller unit. Record measurement equivalents in a two column table. <em>For example, know that 1 ft is 12 times as long as 1 in. Express the length of a 4 ft snake as 48 in. Generate a conversion table for feet and inches listing the number pairs (1, 12), (2, 24), (3, 36), …</em>
- 4.MD.A.1·Know relative sizes of measurement units within one system of units including km, m, cm; kg, g; lb, oz.; l, ml; hr, min, sec. Within a single system of measurement, express measurements in a larger unit in terms of a smaller unit. Record measurement equivalents in a two-column table. <span>For example, know that 1 ft is 12 times as long as 1 in. Express the length of a 4 ft snake as 48 in. Generate a conversion table for feet and inches listing the number pairs <span class="math">\((1, 12)\)</span>, <span class="math">\((2, 24)\)</span>, <span class="math">\((3, 36)\)</span>, …</span>