Measurement of
Length
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Name____________________
Period_______
Examine a meter stick. Notice that it is divided into one hundred equalnumbered parts. Each numbered division is one centimeter (cm) long. Thus, one
centimeter is 0.01 m. Each centimeter is divided into ten equal nonnumbered parts
called millimeters (mm). Therefore, one millimeter is 0.001 m. The length along the
meter stick between 10.0 cm and 12.5 cm is 2.5 cm. This same length can also be
expressed as 25 mm, 0.025 m, and 2.5 x 10–2 m.
When you measure your wood block, do not use the ends of the metric ruler,
because the ends may be damaged or stamped improperly. For a more accurate
reading, use another marking farther along the ruler (Figure 1). Be sure to subtract
your reading of the first mark from your final reading. In measuring with the metric
ruler, notice that the ruler is placed on its marked edge. This helps to eliminate errors
that can arise by viewing the scale from different angles. The apparent shift in position
of an object when it is viewed from different angles is called parallax. Follow this same
procedure for all measurements of length.
Objectives
During this investigation you will
gain familiarity with the metric system of measurement.
practice the proper expression of measured values and results of calculations by
observing the use of significant digits.
Materials
Meter Stick
Metric ruler
2 books
2 wood blocks
Vernier Calipers
Procedure
1.
Measure and record in Table 1-1 the length, width, and height in centimeters of
two different wood blocks. While making each measurement, read the metric
ruler to the nearest millimeter and then estimate to a tenth of a millimeter. The
final estimated reading and all figures to the left of it are significant.
2.
Calculate the volume of each block. Retain in your product only as many
significant digits as you have in the value for one dimension of the block. Record
the volume of each block in cubic centimeters (cm3) in Table 1-1.
3.
In Table 1-2 express the dimensions of the above blocks in meters and the volume
of each of the two blocks in cubic meters (m3).
4.
Measure the thicknesses of 50, 100, and 150 sheets of a book in centimeters and
determine the average thickness of a single sheet. Repeat this process using a
book with pages that vary greatly in thickness from the first book. Record your
results in Tables 1-3 and 1-4.
5.
Using vernier calipers, measure the thickness of 50, 100, and 150 sheets from each
book. Record your values in Table 1-5.
Data and Calculations
Table 1-1
Data
Length
(cm)
Block A
Block B
Width
(cm)
Height
(cm)
Calculations
Volume
(cm3)
Table 1-2
Data
Length
(cm)
Width
(cm)
Height
(cm)
Calculations
Volume
(cm3)
Block A
Block B
Table 1-3 (Book A)
Data
Number of
Sheets
Total Thickness
(cm)
Calculations
Average thickness of
a single sheet (cm)
50
100
150
Table 1-4 (Book B)
Data
Number of
Sheets
50
100
150
Total Thickness
(cm)
Calculations
Average thickness of
a single sheet (cm)
Table 1-5
Data
50
Sheets
100
Sheets
150
Sheets
Calculations
Average thickness of
a single sheet (cm)
Book A
Book B
Interpretation
1.
Why is it not a good idea to use either end of a meter stick or ruler when
measuring length?
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2.
Express the length, width, and height of Block A in millimeters. What is the
volume of Block A in cubic millimeters?
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3.
How many cubic millimeters are in a cubic centimeter?
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4.
How many cubic centimeters are in a cubic meter?
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5.
Suppose that you are measuring the length of a wood block and the edge of your
block appears to be lined up exactly with a millimeter mark. How would you
express the estimated part of a millimeter when you record the block’s length?
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6.
How well do the average thicknesses of a single sheet of a given book (Table 1-3)
compare? Would you assume from this that all the sheets of that book are of
equal thickness?
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7.
If the three values for the average thickness of a single sheet in a given book as
recorded in Table 1-3 are slightly different, which value do you think is the most
reliable? Explain.
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8.
If the values for the average thickness of a single sheet of Book A as recorded in
Tables 1-3 and 1-5 are different, which value do you think is most reliable?
Explain.
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9.
State the most acceptable value for each of the following readings.