Formative Assessment

Do students understand that the volume of 8cc of plastic modeling clay stays the same even if you change the shape?

Listen to the students' discussion of their new 8cc plastic modeling clay shapes as evidence of their current understanding of volume. Joan listens for these ideas as she interprets their responses to her questions. Note that all the sculptures on Joan's tray have the same 8cc volume.

• The volume is the same even if you change the shape, because you haven't added any plastic modeling clay or taken any away.
• Even though the shapes look different, the volume of the plastic modeling clay is still the same - 8 ccs.
• The volumes are not the same because the new shape looks like it takes up more space (inaccurate).

As a next step, Joan shows a tray holding all of the 8cc objects and asks, "If I made a volume line, where would we put each of these objects?"