Find other circles. Go back to the case of four clay balls. Have the students connect the four balls with exactly six toothpicks. Students learn about the idea of three-dimensional curving and why soap films always look flat or like little saddles. At the end of the project they can try these out.
Students can also bring a cottage cheese container.
Make a circle with the wire and dip it into the soap film. Ask the students to remark on the shape of the surface film that arises. Look closely at the film. Blow gently on one side of the film. The film appears to have the elasticity of a rubber sheet.