Hands-on Activity: Shapes of Strength
Educational Standards :
Learning Objectives (Return to Contents)
After this activity, students should be able to:
Materials List (Return to Contents)
For each group:
For the class to share:
For class demonstration by teacher:
Introduction/Motivation (Return to Contents)
Engineers are constantly being challenged to solve the world's new and complicated problems. Many of these problems initially seem impossible to solve, but engineers find a way to make things happen! In the 20th century, engineers developed previously unimaginable things such as electricity, mass transportation, thousands of different automobiles, and even space travel. Engineers often look back in history to learn from past engineering successes and failures as they design and build amazing new things. Every day, engineers are thinking of ways to improve on what already exists as well as developing brand new ideas that have never been created before. In 2003, the tallest building in the world, the Taipei 101, was completed (see Figure 1). Located in Taiwan, the Taipei 101—named for its 101 floors—stands at 1,671 feet, more than a quarter mile tall! For engineers to come up with a plan for this building (and other similarly challenging structures), they must be creative and think "outside the box."
Let's talk about buildings. What makes a building strong? (If students give answers regarding the materials used [concrete, steel, wood, etc.], continue to ask questions leading them towards the idea of shapes.)] What else, besides the materials used, makes the building strong? Let's brainstorm some ideas. Consider the pyramids in Egypt. Those buildings are very strong and have lasted hundreds of years. They have a very distinctive shape that aids in their strength. Structures must be able to remain standing despite large amounts of force put on them by weight and other factors such as earthquakes or wind. Using different geometric shapes, structures are supported in different ways.
An example of a building using two different shapes, triangles and columns, is the Parthenon, a very successful engineering feat. The Parthenon began construction over two thousand years ago in 447 BC—at the height of the Athenian empire—and is still standing today (see Figure 2). The Parthenon was a temple built to represent the power and strength of the residents of Athens, Greece. This is an excellent example of a well-built structure that engineers can study, enabling them to learn better designs from the past for the future.
Now that we've brainstormed for a little while, let's begin our activity. Today you all are going to be engineers with a specific problem: you must build a structure to hold up as many books as possible using only the materials provided. To solve this problem, think like an engineer. As you work with your team, follow the engineering design process—be creative and think "outside of the box." Remember to keep in mind other things that make buildings strong, besides the materials. And, do not be deceived by using paper and straws to build a structure; paper is very strong when used to its best advantage! (Hint: think shapes; see Figure 3.)
Procedure (Return to Contents)
Before the Activity
With the Students
Rule 1: Postpone and withhold your judgment of ideas.
Rule 2: Encourage wild and exaggerated ideas.
Rule 3: Quantity of ideas counts at this stage—not quality.
Rule 4: Build on the ideas put forward by others.
Rule 5: Every person and every idea has equal worth.
Attachments (Return to Contents)
Safety Issues (Return to Contents)
Use caution when cutting straws with scissors.
Troubleshooting Tips (Return to Contents)
If doing this activity as part of the Olympic Engineering unit, gear your examples towards the Olympics by showing pictures from Olympic sites and cities.
If part of a structure is carrying more weight than the rest, the structure will most likely fail faster and not be able to hold as much as when the structure is loaded evenly. Point out that how the structure is loaded with weight plays an important role in its success or failure.
If students get frustrated during the first attempt, shorten the building time.
If students do not find success on the second attempt, encourage them to learn from the design models of other successful groups. Ensure that they understand the relevance of different shapes and their strengths. If time allows, give the group the opportunity to build one last design after they understand the concepts.
Assessment (Return to Contents)
Discussion Questions: Solicit, integrate and summarize student responses.
Activity Embedded Assessment
Design Process: Before the re-design, ask the students to write out the design process for their designs. What is the need? How is the problem defined? If the students are having trouble, do the first few steps with the whole class.
Re-Design Practice: Have the students list any design or fabrication changes they would make to the structures. Have them consider buildings and structures they see in their everyday life. Are there any similar characteristics shared by the different buildings? (Encourage the students to think about triangles and pillars/columns.)
Presentation: Have the students give a short 1-2 minute presentation about their design to the class. In the presentation, ask them to explain some of the cool features of their projects and show which shapes they used to make their structure strong. Have them tell the class how many books their structures were able to hold and describe the failure mode of their designs. (Figure 5 shows the three types of failure modes. Most structures fail by buckling and a few by compression.) Have them give a few ideas of how they could make their structure even stronger (i.e., by adding more columns, thicker columns or triangles).
Discussion: Talk as a class about some of the ideas that could be used to make the structures stronger. Show some pictures of buildings that utilize the different (and strong) shapes. If you are doing this as part of the Introduction to Engineering unit on the Olympics, show examples from Athens, Turin, Beijing and other Olympic cities to keep with the theme. A great U.S. example is the D.C. capitol building that uses pillars, triangles, arches and domes! As each group presents, a list compiled a list of their ideas, which the class may review once the presentations are finished.
Activity Extensions (Return to Contents)
Have students calculate how much taller the Taipei 101 tower is than their school building. (Answer: The average classroom is about 15 feet tall. 1671/15 = 111.4 times taller.) Then figure out how many fourth-grade students it would take standing on each other's shoulders to reach the top of the Taipei 101 Tower. (Answer: Take the average height of the class and divide into 1671 to see how many students it would take to reach 1,671 feet tall.)
Have the students think of other shapes that appear in structures. What about arches and domes? Or more simple shapes like octagons and hexagons? Which shape do they think is the strongest? Have the students build and test their own shapes.
Have the students research structural engineers and create a list of five projects they might have worked on.
Activity Scaling (Return to Contents)
References (Return to Contents)
Taipei 101, Understanding Health Cities. 2005 Taipei City Government. Accessed October 17, 2006. english.taipei.gov.tw/MP_100002.html
ContributorsTod Sullivan, Melissa Straten, Katherine Beggs, Denali Lander, Abigail Watrous, Janet Yowell
Copyright© 2006 by Regents of the University of Colorado
Supporting Program (Return to Contents)Integrated Teaching and Learning Program and Laboratory, University of Colorado Boulder
Acknowledgements (Return to Contents)
This digital library curriculum was developed under grants from the Fund for the Improvement of Postsecondary Education (FIPSE), U.S. Department of Education, and National Science Foundation (GK-12 grant no. 0338326). However, these contents do not necessarily represent the policies of the Department of Education or National Science Foundation, and you should not assume endorsement by the federal government.