Teacher’s Notes
Objective:
In this activity, students practice using metric rulers and meter sticks to learn how scientists use these tools to make measurements.
Suggested Materials
Per Group:
• metric ruler
• meter stick
Purpose
Metric rulers and meter sticks are used to measure short lengths and distances. Both devices are marked in centimeters and millimeters. Metric rulers are generally 15 cm (6 inches) and 30 cm (12 inches) long, while meter sticks are 1 meter (about 1 yard) long. Students should understand that accurate and precise measurements of length and distance are very important for scientific investigations. Common scientific uses include measuring dimensions of things such as leaves, insects, fossils, tracks, and rock layers, and in construction during engineering and laboratory projects. In the
K–5 classroom, students will use the tools for measuring things such as plant growth and the travel distance of various objects. The tools can also be used to calculate areas and volumes.
Many metric rulers and meter sticks also have measurements in Imperial (also known as English or customary) units such as inches and feet. The metric system of measurement is based on measurements divided by units of ten (decimal). The base unit in metric systems, such as the meter for length or the gram for mass, is also based upon constants. In contrast, the foot is based upon the historical measure of a specific individual and throughout history, different countries, regions, and even cities have had different lengths for a “foot,” which meant it was far from a consistent measure.
Students may not immediately understand that the choice of tool depends on the scale of the object being measured. Rulers are useful for objects between about 1 mm and the total length of the ruler, while meter sticks are useful between 1 cm and 100 cm (1 m). Neither can be used for microscopic measurements, and neither is practical for measurements greater than a few meters.
Discovery Education Science
Page 1 of 3
 Discovery Communications, LLC

Teacher’s Notes
Use
When measuring an object or a distance with a metric ruler or meter stick, put one end of the object at the 0 (zero) centimeter mark. Check to see where the other end of the object is located. This is the length of the object. Be aware that students may have trouble keeping the object and tool steady during measuring. As groups are working on their measurements, make sure they maintain good contact between the 0 mark and the end of the object they are measuring. Also be aware that old rulers may be eroded at the end such that the end of the ruler is not actually at the 0 mark. If this is the case, guide students to use another starting point, like 1 cm, and subtract the starting measurement from the total as needed.
Verify that students are using the correct units (centimeters or millimeters) when performing and recording measurements, in particular when using tools that include both metric and Imperial scales.
Student should also be guided to record not only the object or distance that they are measuring, but also the dimension (length, width, or height).
In the example below, the nail is ______ centimeters long. (Answer: 7.3)
Practice
After modeling how to use a ruler and meter stick, have students practice using metric rulers and meter sticks by measuring common objects and distances in the classroom such as the length of a pencil, width of a desk, height of a classmate, width of the room. It is best if they measure objects and distances with a variety of scale in order to see what each tool is useful for and what it is not useful for.
•
Have students measure each object using the ruler and the meter stick. Guide them to record their measurements in a table in order compare them easily.
•
Have students analyze the measurements: o Which was shortest? Which was longest?
o Were the measurements using the meter stick the same as those using the ruler?
o Which tool was easier to use?
• Have students think about what the tools are useful for and what they are not useful for: o Would you want to use a meter stick to measure the distance between your home and your school? Why or why not? o Could you use a ruler to measure width of an ant’s leg?
•
What else would you like to measure with a metric ruler or meter stick? Why? What do you think you would find out by measuring with a metric ruler or meter stick?
Discovery Education Science
Page 2 of 3
 Discovery Communications, LLC

Teacher’s Notes
•
What questions could you answer using a metric ruler or meter stick?
•
What questions can’t a metric ruler or meter stick help you answer?
•
Why might a scientist who studies dinosaur tracks carry around a ruler?
• If students are ready, have them use the ruler or meter stick to calculate the area of a plane or the volume of a rectangular solid.
Discovery Education Science
Page 3 of 3
 Discovery Communications, LLC