Mathematics Resource Guide Grades 3-5
Making Metric and Customary Rulers
Strand B: Measurement
Benchmark MA.B.1.2.1: The student uses concrete and graphic models to develop
procedures for solving problems related to measurement including length,
weight, time, temperature, perimeter, area, volume, and angles.
Grade Level Expectations: The student:
•
knows measurement concepts and can use oral and written language to
communicate them.
•
uses a wide variety of models (for example, manipulatives, and diagrams) and
applies counting procedures to investigate measurements of length, area,
volume, and perimeter.
Overview:
In this lesson students make metric and customary rulers of various lengths.
A ruler is a straight-edge (usually wood, metal, or plastic) used for
measuring lengths and for drawing straight lines. Rulers can show two
measurement systems. Inches are often along one border while centimeters
are along the opposite border. You can measure the same object to the
1
1
1
inch,
inch, or even
inch, depending upon the scale of
nearest inch,
2
4
16
your ruler. To measure the length of an object, line up the left edge of the
ruler (where zero would be) with the left-edge of the object. The
corresponding number below the right edge of the object is called the
measure of that object. Children should have many experiences with
different units of measurement (e.g., centimeters, inches, decimeters, feet,
yards, and meters.) Students should use these tools throughout the school
year in mathematics and other content areas.
Materials:
•
12-inch Rulers (The best to use will have centimeters on one side and inches
on the other.)
•
Construction Paper Cut into Two-Inch Strips — Two or More Colors
•
Glue
•
Markers
Division of Mathematics and Science Education
Making Metric and Customary Rulers
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Mathematics Resource Guide Grades 3-5
•
•
•
•
Meter sticks
Elongated Tag Board (poster board) Cut into Three-Inch or Five-Centimeter
Strips
Tape Measures
Yardsticks
Procedures:
1.
To create these measurement tools (rulers), children need to use actual
measurement tools, construction-paper strips, and the tag-board strips. The
tag-board strips should be at least one inch wider than the constructionpaper strips. Have some of the students cut construction-paper strips into
one-inch pieces. Have other students cut the construction-paper strip into
five-cm pieces. Cut these pieces in two different colors.
2.
Model how the students might make a ruler. Glue the colored units end-toend on a tag-board strip. These can be of any length, but students will be
most successful if they make shorter rulers first. After gluing the colored
units on in alternating colors, label the rulers with numbers (see below for an
example of a ruler with 5 cm units).
0
3.
5
5.
15
20
25
30
Providing minimal guidance on ruler construction will allow you to gain insight
into students’ understanding. The students will construct the rulers in
different ways, and asking them to explain their reasons for constructing
them in a certain way provides an excellent informal assessment of their
understanding of the measurement process. Below is an example of a ruler
that may be constructed that would work for a student.
5
4.
10
10
15
20
25
30
Note the absence of the zero and the number label in the middle of the unit
rather than at the gradient line.
Allow the students time to create a variety of rulers. These may vary from
small (6-inch) to quite large (5-foot) rulers. When finished, the class will
have a collection of rulers that can be used for many different measurement
Division of Mathematics and Science Education
Making Metric and Customary Rulers
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Mathematics Resource Guide Grades 3-5
6.
7.
activities. Note: In the first example above (in step #2), the zero has been
placed on the ruler. Many rulers do not have this mark and students must be
clear on where the imaginary zero is and where to begin measuring. When
teaching how to use a ruler, be sure students are clear that the purpose of
using a ruler is to measure units. Understanding this concept and being able
to determine where to begin measuring with the ruler is essential in order to
measure accurately.
Next, provide an activity whereby the class can test their rulers. Have the
students work in pairs and give each pair an object to measure. More than
one pair should measure the same object. Ask one member of the pair to
measure with a commercial ruler and the other member of the team to
measure with a class-constructed ruler. After everyone has measured,
compare the results. This analysis can provide an excellent discussion on why
measurements might vary. Ask the students to consider why there may be
two different results. Responses may vary from inaccurate measuring to
poorly constructed rulers to inaccurate counting. Another concept to discuss
is why the results should be the same.
It is important to allow frequent practice with the rulers the students have
made. Keep the class-made rulers accessible in a measurement center.
Students can be assigned measurement tasks throughout the school year.
Have several different students measure the same object and compare
results. An interesting task is to have a group or pair of students create a
written description of the size of the classroom or playground and share
this description with another class. Have several teams do this, compare
their answers, and see what makes the most sense, and why.
Literature: Carrie Measures Up by Linda Williams Abner (ISBN: 1-57565-100-9);
Inch by Inch by Leo Lionni (ISBN: 0-688-13284-7)
Assessment:
•
Have students measure three different objects using the centimeter and
inch ruler. Have them explain their findings.
Extension:
•
Students can measure objects that are longer than the class-constructed
tool they will use (e.g., measure the length of a wall with a 20-inch ruler).
Observe how the student determines how to measure the length. Explore
measurements with other tools such as clocks, scales, etc.
Division of Mathematics and Science Education
Making Metric and Customary Rulers
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