LER 9301
Ages Grades
5+
K+
Demonstration Ruler
The Demonstration Ruler is great for modeling linear measurement.
Track measurements from 0–18 inches (in.) or 0–45 centimeters/centimetres (cm)
with the adjustable red band. Display the Demonstration Ruler on any magnetic
receptive surface, such as a white board.
Suggested Use
Discuss with students some earlier methods of measurement, such as gauging
length with thumbs and feet. Guide students in measuring a few smaller objects
using the width of their thumbs. Record and compare the results. Lead students to
the conclusion that everyone’s thumb width is not the same. Therefore, a
“standard” unit, such as inches or centimeters/centimetres, is necessary for
everyone to achieve the same measurements.
• Familiarize students to the ruler and its markings.
• Be sure to identify by which units you are measuring (in. or cm).
• If using a white board, draw a line on the board and position the ruler
underneath.
• Align the left end of the line to 0 on the left end of the ruler.
• When measuring, always hide the red band from view (as close to 0 as
possible).
• Gently slide the band from left to right and align the end of the red band with
the end of the line or object being measured.
• Emphasize that the left end of the object or line being measured must always be
“flush” (even) with 0 on the left end of the ruler.
• Students should recognize that accurate
measurements begin on 0, which is usually
(but not always) on the left edge of the ruler.
• You may need to remove the ruler from the
magnetic surface while adjusting the length of
the red band.
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