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CHAPTER 5
1
Measuring Length
STUDENT BOOK PAGES 142–143
Guided Activity
Goal Select an appropriate measuring unit.
Prerequisite Skills/Concepts
Expectations
• Know metric length units
(kilometre, metre, centimetre,
millimetre).
• select and justify the appropriate metric unit to measure length or distance in a
given real-life situation
Assessment for Feedback
What You Will See Students Doing…
Students will
When Students Understand
If Students Misunderstand
• select an appropriate unit for measuring length
• Students will select a unit of appropriate linear
measure for a specific context.
• Students will choose an inappropriate linear unit of
measure. Provide these students with rulers, metre
sticks, or measuring tapes so they can measure
different items, long and short, and become familiar
with each unit of measure (kilometre, decametre,
metre, decimetre, centimetre, and millimetre).
Students can also look at the different units of
measure on their rulers and compare the sizes of
the different units. This will help them visualize
the size of each unit of measure.
Preparation and Planning
Pacing
10–15 min Introduction
10–15 min Teaching and Learning
20–30 min Consolidation
Materials
•Rulers, tape measures, metre sticks
•Optional: road map or atlas;
smaller items to measure
•Optional: rulers or tape measures
marked in cm and mm, 1/pair
Masters
•Optional: Chapter 5 Mental
Math p. 55
•Optional: Measuring Length
Cards (Master) p. 62
•Assessment: Problem Solving/
Thinking Rubric, Masters
Booklet p. 8
Workbook
p. 42
Key
Assessment
of Learning
Question
Question 8, Application of Learning
Meeting Individual Needs
Extra Challenge
• Students may be challenged to design a poster to help classmates choose
an appropriate unit for measuring length. They could show examples with
graphics of things that can appropriately be measured with specific units.
• Students may want to share information about Western rain forests with
the class. Direct these students to the following Web sites:
• www.nps.gov/olym/edurain.htm
• http://curriculum.calstatela.edu/courses/builders/lessons/less/biomes/
rainforest/temp_rain/temprain.html
• www.arbutusartsofthegulfislands.com/ftree.html
Extra Support
• Provide students with Measuring Length Cards (Master) p. 62. Have
students cut apart cards and match cards with the name of an item to be
measured with the appropriate unit. Ask students to explain their reasoning
for their choice of unit. Alternately, students can work in pairs to quiz
each other on matching the cards.
Mathematical Reflecting, Selecting Tools
Processes
and Computational Strategies,
Representing, Communicating
Copyright © 2006 by Thomson Nelson
Lesson 1: Measuring Length
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1.
Introduction (Whole Class)
➧ 10–15 min
Display a road map or atlas and a number of smaller items of
varying sizes. Explain to students that in today’s lesson they
will be selecting appropriate units for measuring length.
If desired, distribute rulers or tape measures for students
to use as reference. Although no actual measuring is required
in this lesson, having a ruler marked in millimetres and
centimetres may help students remember the relationship
between the units.
Sample Discourse
“Let’s think about measuring length or distance. What is
the most appropriate unit for measuring distance?”
• A map or atlas can tell us distances from one city or place
to another. The distances are measured in kilometres.
• One kilometre is equivalent to 1000 m.
“Sometimes personal referents, or measures to which we
can relate, gives us a sense of how far 1 km is. What route
in our community is about 1 km?”
• It’s about 1 km from my house to the school.
• It’s about 0.5 km from my home to the school, so if I walk
to school and back, that’s about 1 km.
“What is the next main smaller metric unit for measuring
length? What could we use as a referent?”
• The metre is the next main unit. A door is about 2 m high
and a bit less than 1 m wide.
• A section of sidewalk is a square about 1 m each side.
“What is the next smaller metric unit for measuring length
and what could we use as a referent?”
• The centimeter is the next unit. My finger is about 1 cm wide.
• My eraser is about 1 cm wide.
“What is the smallest metric unit for measuring length
that we use? What could we think of as a referent?”
• The millimetre is the smallest unit we use for measuring length.
I stacked up 10 dimes and then measured the height. It was
about 11 mm, so the thickness of 1 dime is just slightly
more than 1 mm.
Tell students that these referents, and any others with
which they are familiar, will be helpful to them in this lesson.
Introduce students to the decametre. Tell them that a
decametre is equivalent to 10 m. Ask them to use one of
their referents to describe 1 dam.
• One section of sidewalk is 1 m wide. Then 10 sidewalk
sections are 1 dam.
Remind them that in this lesson, they will be learning
about selecting appropriate measuring units.
2.
Teaching and Learning (Pairs)
➧ 10–15 min
Ask students to turn to Student Book page 142. As a class,
read the context and the central question. Encourage students
to examine the photos carefully for referents, as many will
not have personal experience with forests. Inform students
that the arbutus is a deciduous tree that is never without
leaves—new ones grow as old ones drop off.
Ask students to explain why they think James might
want to use decametres to measure the length around the
base of the tree.
Have students work in pairs to complete prompts A to F.
Before completing the Reflecting questions, gather as a whole
class to share solutions. This will provide an opportunity
to assess students’ ability to select the appropriate unit
of measure.
Reflecting
Here students reflect on the metric units of linear
measurement and their use. Allow time for discussion
before having students record their answers.
14
Chapter 5: Measuring Length
Copyright © 2006 by Thomson Nelson
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3.
Consolidation ➧ 20–30 min
For intervention strategies, refer to Meeting Individual
Needs or the Assessment for Feedback chart.
Closing (Whole Class)
Have students summarize their learning considering a
different context and relating it to metric units of linear
measurement. For example, they might respond to the
following prompt:
“We can measure the length of different things in our
classroom using different units.
• Some things we can measure in kilometres are …; some
things we can measure in metres are …; some things we can
measure in centimetres are …; and some things we can
measure in millimetres are …”
4.
Key Assessment of Learning Question (See chart on p. 16.)
5.
Answers
A. I would use metres to describe the height of the trees.
For example, the tree looks too tall to measure it in
centimetres. Kilometres are used to measure long distances
and the tree is a lot shorter than a kilometre. The unit in
between centimetres and kilometres is metres.
B. I would use kilometres to describe the distance travelled.
For example, if I use a map to find the distance, the scale
on the map is in kilometres.
C. I would use millimetres to describe the thickness. For
example, if the bark is very thin, then it is probably less
than 1 cm thick, so it would make sense to use millimetres,
which is smaller than centimetres.
D. I would use millimetres to describe the thickness.
For example, a leaf is very thin, so it would make
sense to use millimetres, which is the smallest unit.
E. For example, the length of a bug, the height of a new
blade of grass, or the width of a small flower petal would
be measured in millimetres.
1. For example, all the units include “metre” because they
are all metric units that describe part of a metre.
2. For example, the leaf was measured to the nearest
millimetre because it was measured to the nearest tenth
of a centimetre and a tenth of a centimetre is a millimetre.
3. For example, different units are appropriate for different
measurements because some things are really big and if
Copyright © 2006 by Thomson Nelson
6.
7.
8.
9.
10.
you measured them in millimetres then the number would
be big. If you measured something really small in kilometres,
you’d get a very small number with lots of decimal places.
a) For example, I would use metres to measure the
height of a room since the height is longer than
a metre stick.
b) For example, I would use millimetres to measure the
thickness of a window since a pane of glass is thin.
c) For example, I would use kilometres to measure the
distance since you would have to drive to measure it.
a) For example, to measure the height of the trees I would
use centimetres if the trees are really young and tiny.
If the trees are at least 1 m tall, I would use metres.
b) For example, to measure the length of the leaves
I would use centimetres since most leaves are at least
a few centimetres long, but they are not so long that
they need to use metres.
a) My math book is over 2 cm thick, my fingernail is
barely 1 mm thick and a pack of 100 sheets of paper is
less than 1 cm thick, so I’d use millimetres for b and c.
For example, a wire is pretty thin, not even 1 cm wide,
so using millimetres makes sense.
a) For example, thickness of a DVD or the diameter
of coins would be measured in millimetres.
b) For example, the length of a videotape or the diameter
of a DVD would be measured in centimetres.
c) For example, the length of an aisle or the height of
the store would be measured in metres.
d) Nothing in the store would be measured in kilometres
since a kilometre is too long.
No. For example, even the CN tower isn’t 1 km tall and
it’s huge.
For example, there should be a unit for hundreds of
metres between decametre and kilometre. Centimetre is
one hundredth of a metre and has an “i” like decimetre,
so the unit for hundreds of metres should be centametre
with an “a,” like decametre.
Lesson 1: Measuring Length
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Assessment of Learning—What to Look for in Student Work…
Assessment Strategy: investigation
Application of Learning
Key Assessment Question 8
• Ryan is in a video store. What items in the store, if any, might be measured in these units?
a) millimetres
b) centimetres
c) metres
d) kilometres
(Score correct responses out of 4.)
Extra Practice and Extension
At Home
• You might assign any of the questions related to this lesson,
which are cross-referenced in the chart below.
• Have students discuss linear measurement with family
members. They could ask for some examples of metric units
of linear measure that are relevant to them, for example, the
distance from home to their workplace or to the home(s) of
relatives or friends, measured in kilometres; the dimensions
of the home, rooms, yard, and so on, measured in metres;
the height, length, or width of pieces of furniture, measured
in centimetres; and the dimensions of very small items, such
as thumb tacks, measured in millimetres.
Mid-Chapter Review
Student Book p. 149, Questions 1 & 2
Skills Bank
Student Book p. 156, Questions 1 & 2
Chapter Review
Student Book p. 160, Questions 1 & 2
Workbook
p. 42, all questions
Nelson Web Site
Visit www.mathK8.nelson.com and follow
the links to Nelson Mathematics 6, Chapter 5.
Optional: Chapter 5
Mental Math p. 55
Math Background
The internationally accepted system of metric units is
called SI (Systeme International). In this system, there is one
base unit for each aspect of measurement. For length, the
SI unit is the metre. Other units are obtained by attaching
various prefixes to the metre. Kilo means a thousand, so
1 kilometre = 1000 metres; deca means ten, so 1 decametre
= 10m; hecto means hundred, so 1 hectometre = 100m;
centi means a hundredth, so 1 centimetre = 0.01 m; and
milli means a thousandth, so 1 millimetre = 0.001 m.
In selecting an appropriate unit for linear measurement,
students need to consider the context. In general, distances
are measured in kilometres; things such as the size of their
classroom are measured in metres; smaller items, such as
small pieces of furniture are measured in centimetres; and
very small items or dimensions, such as the thickness of a
sheet of bristol board, are measured in millimetres.
All measurements are approximations. The degree of
accuracy required varies in different situations. In some
contexts, great accuracy is required. For example, if the
length of a pencil is 12.4 cm, its length had been measured
to the nearest millimetre or tenth of a centimetre.
16
Chapter 5: Measuring Length
Assessment:
Problem Solving/
Thinking Rubric,
Masters Booklet p. 8
Optional:
Measuring Length Cards
(Master) p. 62
Copyright © 2006 by Thomson Nelson