Students
use the inclinometer
to measure
the height
of the school's
flagpole,
four times.
The inclinometer
is used by
holding it
at arm's length
and sighting
along the
top of the
flagpole.
Locate a position
where the
angle is 45
degrees and
then walk
from that
spot to the
flagpole,
counting the
number of
paces. The
height of
the flagpole
is then the
sum of the
number of
paces (expressed
in feet) and
the person's
height (also
expressed
in feet).
Pacing .
The unit of
length measure
is a pace ,
introduced
to create
another visible
source of
prospective
measurement
error. A pace
is a simple
method of
measuring
linear distance
by walking.
A pace equals
two normal
steps, beginning
and ending
on the same
foot. It is
measured from
the heel of
the foot to
the heel of
the same foot
in the next
stride. It
is easiest
if the pacer
says "and" during
the first
step, then
the number
at the end
of the second
step (and
one, and two.).
Pacing can
be used anywhere:
indoors, outdoors,
in the woods,
or in open
fields. Pacing
dates back
to Roman times.
The original
Roman pace
was slightly
over 58 inches
long. This
has become
known as the
geometric
pace, which
measures about
5 feet for
most people.
To
obtain the
measure of
a person's
pace, a few
methods can
be used. One
is to set
up a course
of 50 feet
with starting
and ending
lines. Start
with the heel
of the foot
touching the
line. Then
have students
pace the distance
and record
the number
of paces.
Teacher's
note. Ask
students
if there
is reason
to pace
the same
distance
more than
once. If
students
believe
that multiple
trials might
be a sound
idea, have
each student
walk the
same 50
feet 5 times,
recording
the number
of paces
each time,
and converting
paces to
feet/pace
(divide
50 feet
by the number
of paces).
Then ask
students
how they
are going
to think
about a "best
estimate" for
the distance
covered
for each
pace. This
is an opportunity
to think
about how
students
think about
measurement
variation.
Students
sight the
flagpole with
the inclinometer
at a 45 degree
angle and
then paces
from that
point to the
flagpole.
Each student
tries this
four times,
each time
from a different
perspective
(so that the
person is
not starting
from the same
place each
time).
Records .
Students
record each
observation
on an index
card. On
the front
of the card
is the measure
in paces.
The back is
the name
of student
and number
of observation.
Students
convert paces
to a common
unit of measure
(e.g., feet)
and add their
height to
each estimate
to obtain
an estimate
of the height
of the flagpole.
