Secrets of Lost Empires I—Inca
To construct suspension cables out of newspaper.
- copy of "Hang in There!" student handout
- four paper clips
- paper cup
- weights (such as washers, coins, books)
- various pieces of string, yarn, thread, twine, or rope
- hole puncher
- two chairs
- sheet of paper
Students can try constructing suspension cables out of strips of newspaper in
Organize students into small groups and
distribute copies of the "Hang in There!" student handout and a set of materials to each group.
Encourage students to look at the weave in samples of thread, string, yarn, and
rope as they investigate ways to increase the weight-bearing strength of
Provide students with weights or washers to test simple
cables. As the amount of weight the cables can sustain increases, students can
suspend heavier objects, such as books. When twisting or braiding strips,
students might want to staple or tape the ends together. Ask students how the
staples or tape might affect the strength of the newspaper and have them think
of ways to combine newspaper strips without these materials.
As an extension of this activity, challenge students to create a strong cable
using a limited amount of newspaper. Give each team the same amount of
newspaper (such as the front section) and have them create a cable that spans 2
m (6.5 ft) and supports the most weight. Ask each team to describe the method
it used and why. Which method(s) sustained the most weight and used the
materials most efficiently? Discuss how sometimes there is no one best design
and how many different designs can meet the challenge.
Students' cable designs will vary. They will find that multiple strips
of newspaper are able to support more weight than a single strip. They should
also notice that many different methods support the same amount of weight.
Students can evaluate methods using criteria such as the most efficient use of
material, the most easily constructed method, or the method that supports the
greatest amount of weight.
Ask students if they've ever crossed a suspension bridge. There are a number of
suspension bridges in the United States, including the George Washington Bridge
in New York City. This bridge spans 1.1 km (3,600 ft) and is supported by four
main cables. Each cable is 1.6 km (1 mi) long and contains 26,000 strands of
steel. If all of the strands that make up the cables were laid end to end, they
would circle the earth four times.