Name ___________________________
Hour ________
Lab Skills: Measuring Length
How do you find the length of an object?
Size matters! When you describe the length of
an object, or the distance between two objects,
you are describing something very important
about the object. Is it as small as a bacteria
(2 micrometers)? Is it a light year away (9.46 !
1015 meters)? By using the metric system you
can quickly see the difference in size between
objects.
Materials
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Metric ruler
Pencil
Paper
Small objects
Calculator
1. Reading the meter scale correctly
Look at the ruler in the picture above. Each small line on the top of the ruler represents one millimeter. Larger lines stand
for 5 millimeter and 10 millimeter intervals. When the object you are measuring falls between the lines, read the number
to the nearest 0.5 millimeter. Practice measuring several objects with your own metric ruler. Compare your results with a
lab partner.
2. Stop and think
a. You may have seen a ruler like this marked in centimeter units. How many millimeters are in one centimeter?
b. Notice that the ruler also has markings for reading the English system. Give an example of when it would be better to
measure with the English system than the metric system. Give a different example of when it would be better to use
the metric system.
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3. Example 1: Measuring objects correctly
Look at the picture above. How long is the building block?
1. Report the length of the building block to the nearest 0.5 millimeters.
2. Convert your answer to centimeters.
3. Convert your answer to meters.
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4. Example 2: Measuring objects correctly
Look at the picture above. How long is the pencil?
1. Report the length of the pencil to the nearest 0.5 millimeters.
2. Challenge: How many building blocks in example 1 will it take to equal the length of the pencil?
3. Challenge: Convert the length of the pencil to inches by dividing your answer by 25.4 millimeters per inch.
5. Example 3: Measuring objects correctly
Look at the picture above. How long is the domino?
1. Report the length of the domino to the nearest 0.5 millimeters.
2. Challenge: How many dominoes will fit end to end on the 30 cm ruler?
6. Practice converting units for length
By completing the examples above you show that you are familiar with some of the prefixes used in the metric system like
milli- and centi-. The table below gives other prefixes you may be less familiar with. Try converting the length of the
domino from millimeters into all the other units given in the table.
Refer to the multiplication factor this way:
• 1 kilometer equals 1000 meters.
• 1000 millimeters equals 1 meter.
1. How many millimeters are in a kilometer?
1000 millimeters per meter ! 1000 meters per kilometer = 1,000,000 millimeters per kilometer
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2. Fill in the table with your multiplication factor by converting millimeters to the unit given. The first one is done
for you.
1000 millimeters per meter ! 10-12 meters per picometer = 10-9 millimeters per picometer
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3. Divide the domino’s length in millimeters by the number in your multiplication factor column. This is the answer
you will put in the last column.
Prefix Symbol
Multiplication
factor
Scientific notation
in meters
Your multiplication
factor
Your domino
length in:
10-9
pm
pico-
p
0.000000000001
10-12
nano-
n
0.000000001
10-9
nm
micro-
!
0.000001
10-6
!m
milli
m
0.001
10-3
mm
centi-
c
0.01
10-2
cm
deci-
d
0.1
10-1
dm
deka-
da
10
101
dam
102
hm
103
km
hectokilo-
h
k
100
1000
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