Volume vs. Number

Est. Class Sessions: 3–4

Developing the Lesson

Part 2. Conduct the Experiment

Collect the Data. Refer students to their drawing and the Volume vs. Number Data Tables page from their Student Activity Book. Ask students to use the information in their drawings to label the tables. See Figure 2.

Students should use a 250 cc graduated cylinder for both experiments and choose a convenient amount of water. A good choice is 140 cc.

Figure 2 shows sample data for small (standard size) marbles in Experiment 1 and large (3/4-inch) spheres in Experiment 2.

If you use marbles that are different sizes than standard marbles or 3/4-inch spheres, you may need to adjust the amount of water in the graduated cylinders.

As students collect the data and complete their data tables, note their abilities to measure volume by displacement to the nearest cubic centimeter. Look for the following:

Do students check that the graduated cylinder is filled with the correct volume of water before adding the marbles? Do they use an eyedropper to add water as necessary?
Do students add the marbles carefully so as not to splash water out of the cylinder?
Do students read the volume in the cylinder at eye level?
Do students compare their measurements with partners to reduce measurement error?

Document students' skills toward measuring volume by displacement to the nearest cubic centimeter [E6].

Graph the Data. Students graph the data from both experiments on a single copy of the Centimeter Graph Paper Master from the Teacher Guide. In addition to the points in the data table, they should add a point at (0, 0) since the volume of 0 marbles is 0 cc (Question 6).

Question 7 instructs students to draw best-fit lines through each set of data points.

The graph for this experiment is very similar to the graphs students drew for Bouncing Ball in Unit 5 and Downhill Racer in Unit 10. They should be ready to make their graphs with very little assistance from you. If you use marbles that are larger than 3/4-inch in diameter, your students may need to use a different scale on the vertical axis.

As students work, check for appropriate scales, labels, and titles. Look also for points that have been plotted correctly and lines that “fit” the points. Figure 3 is a graph of the sample data in Figure 2.

Student Guide: 562 563

Answers