Measuring Volume

Est. Class Sessions: 3–4

Developing the Lesson

Part 2: Measure Volume

Draw a Picture. Briefly summarize the procedure students will use to measure the volume:

Fill a graduated cylinder to a water level of 80 cc.
Place an object in the graduated cylinder.
Read the meniscus.
Determine the volume of the object.

Display all the objects from a set of those you've gathered. Then instruct students to draw a picture communicating the important elements of the investigation on the Draw section of the Measuring Volume pages in the Student Activity Book. Students need to include the graduated cylinder, indicating measurements in "cc," as well as a labeled drawing of the objects they select for study. An example of a student's drawing is shown in Figure 2. Note that the student labeled the two main variables: O for Object and V for Volume.

Collect the Data. After drawing the picture, student pairs are ready to begin the investigation. All students should measure a train of centimeter cubes because they can determine its volume before placing the object in the graduated cylinder. Use a display of the table in Question 2 and guide students to complete the data tables on their own pages.

Fill in information on the display where appropriate as you ask the following prompts:

What is the unit of measurement in this lab?

Have students write "cc" for cubic centimeters on the appropriate lines in the top row of the data table:

On the first row of the data table, fill in the number of connecting cubes on the blank line to tell how many connecting cubes are in the train in the set you and your partner will use.
What objects are you going measure? What will you write on the lines in the first column of your data table before you begin? (the name of the objects and how many of each; For example, 3 hex nuts)
Look at at the second column. What is the volume of the water in the graduated cylinder at the start? (80 cc)
Look at the third column. If I add an object to the graduated cylinder, how will you find the volume of the water and the objects? (Possible response: I will read the graduated cylinder.)
Look at the fourth column. How will you find the volume of the objects? (Possible response: I take the volume of the water away from the total volume.)
Look at the last column. How can I show this in a number sentence? (Possible responses: I will write a subtraction number sentence: 100 cc − 80 cc = 20 cc; I will write an addition number sentence to find the unknown volume: 80 cc + 20 cc = 100 cc.)
What kind of number sentences will you write in the fourth column? (They could be addition or subtraction number sentences.)

Ask students to use a crayon or pencil to make a box around the fourth column in the Measuring Volume data table. Then students can easily see which number to represent on the graph.

Next have student pairs measure the volume of the objects they chose and record their data in the Measuring Volume data table. Figure 3 shows a sample data table fully labeled and filled in with data. After students complete their data tables, check their work for accuracy by comparing values found by different pairs. Have several pairs explain how they found the volume of an object.

Graph the Data. Show the display of the Bar Graph Master as students refer to Question 3. Discuss what information from their data tables should be included on their graphs.

Ask questions similar to the following:

What are the variables in this investigation? (Type of object (O), volume of water, total volume, and volume of the set of objects (V).)
What information in your data table changes? (The type of object, the total volume, and the volume of the object.)
What about the volume of the water? (That doesn't change; it is always 80 cc.)
What variable should you put on the horizontal axis? (type of objects)
What letter do you use to represent this variable? (O for objects)
What variable should you put on the vertical axis? There are two other variables that change. Which one should we use? What are we most interested in finding out? (volume of each object)
What letter should you use to represent the volume of the object? (V for volume)

Students will need to decide how to scale the vertical axis. The scale will depend on the range of volumes found for the objects. Most likely they will scale the vertical axis by ones. Students can write the type of object or draw a picture of it in the appropriate spaces along the horizontal axis. Figure 4 shows a sample graph.

Adventure Book:

Student Activity Book: 567 568 569

Answers