2nd Grade Unit- Measurement and Data
Charlotte Mecklenburg Schools
Lesson #8: Moving to Metric (adapted from Investigations Unit 9: Session 3.4)
Cluster: Measure and estimate lengths in standard units.
Standards:
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.2. Measure the length of an object twice, using length units of
different lengths for the two measurements; describe how the two
measurements relate to the size of the unit chosen.
2.MD.3. Estimate lengths using units of inches, feet, centimeters,
and meters.
Standards for Mathematical Practice
Mathematical Goal:
Students will be introduced to and become familiar with the terms
centimeters and meters as standard units of measure.
Students will use centimeters and meters to describe length
Materials:
M16
World map or globe (optional)
Centimeter cubes
Rulers and meter sticks
Meter strip
Scissors
Tape
SAB p. 43-46
Charts: “Things About 1 Centimeter Long in School”
“Things About 1 Meter Long in School”
SMP.1 Make sense of problems and persevere in
solving them
SMP.4 Model with mathematics
SMP.6 Attend to precision
Words you should hear students use in mathematical
conversations:
metric system
centimeter
meter
Classroom Routine: What Time Is It?: What Time Will It Be?
Write 2:00 on the board and ask pairs to set their clocks to that time.
Then, introduce students to the quarter hour by asking:
 What would the clock look like if the minute hand only went 15 minutes past 2:00?
Write 2:15 on the board
 Does anyone know what time this is? This time is 2:15 or 15 minutes past 2:00.
On the demonstration clock, move the minute hand 15 minutes counting by ones as you go. Highlight that the hour
hand is slightly past the 2, indicating that it is not exactly 2:00, but some minutes past 2:00. Repeat with 1:00, 6:00 and
12:00. Students work in pairs setting their clocks to 15 minutes past the hour and writing the new time in digital
notation.
Before:
Remind students about the story “The King’s Foot” when the king and the carpenter had different ideas of how large the
horse stall should be. They had a problem because their feet were different sizes and they couldn’t agree whose foot to use
to measure.
Students should be introduced to the metric system of measurement which uses centimeters and meters instead of inches,
feet and yards. There is a great explanation about the metric system on page 158 of Unit Guide 9.
Show students what a centimeter is using centimeter cubes or centimeter grid paper.
Using the centimeter side of a ruler, students should practice measuring the centimeter with the cubes or centimeter grid
paper in order to gain an understanding of the size of a centimeter. They should practice measuring several objects that
17
2nd Grade Unit- Measurement and Data
Charlotte Mecklenburg Schools
can easily be measured using centimeters and understand that the centimeter is used to measure small objects.
The teacher should construct a meter strip using 100 centimeters put together. (use 3 centimeters width instead of just 1 so
the strip does not tear too easily) Show students that a meter is a little longer than a yard by comparing the yardstick and
meter strip.
During:
Discuss as a group, what a meter is (100 centimeters) and ask students to discuss with their partner, how we could create
a meter strip using the centimeter grid paper. (they should realize that adding 5 strips of 20 cm together will make a meter
strip).
Using the centimeter grid paper, students should construct a meter strip by connecting 100 centimeters together. Instead of
making the strip one cm wide which will tear easily, use a width of 3 centimeters. Students will see that one meter is the
same as 100 centimeters. They can practice measuring with the meter strip by finding different objects in the classroom
that measure approximately 1 meter. If you have enough meter sticks, have students measure with those in the classroom
and have them save their meter strips to measure objects at home since they will tear easily.
Emphasize the need to estimate the length of an object before measuring it.
After:
Students should work on SAB pp. 43-45 and complete SAB p.46 for homework using their meter strips.
As a group discuss the different units of measure on a ruler (inches are larger than centimeters therefore there are more
centimeters on the ruler than inches)
Discuss how we know when to use centimeters and when to use meters to measure objects. (Use centimeters to measure
small objects and meters to measure larger objects)
Writing Task: Does it take more centimeters or meters to measure the length of the classroom? Explain how you know?
(this is the compensatory principle)
18