Students continue to explore the investigation question, this time using a different material: plastic modeling clay.

Give each student approximately 10 cubic centimeters of plastic modeling clay. Have students use their plastic knife to help them shape the plastic modeling clay into eight individual centimeter cubes. They can use the wooden cubes as models.

As they finish, have students return the excess plastic modeling clay to a central location.

Check understanding:

• How much plastic modeling clay do you have?

• 8 centimeter cubes = 8 cubic centimeters

Tell students that they now have a new challenge: To create a new building, this time using their plastic modeling clay cubes. There are just two rules:

1. They must use all eight cubes
2. They must keep four of the cubes in cube shape, but they can change the shape of the other four cubes in any way they please.

Point out that since the plastic modeling clay cubes stick together — and can be squeezed and poked — students will be able to make shapes that were not possible when they were using the wooden cubes.

As they finish, have students place their constructions on a large piece of paper in the class meeting area and gather there for discussion.