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Cross that Bridge!

Grades: 5-8
Author: Kathy Crooks
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Module Description

This inquiry activity introduces participants to different hands-on building activities. The participants will review what is meant by "constraints" and will brainstorm constraints that might affect the building of structures. Participants will review and discuss how these activities can be adapted for use in a variety of content areas. Throughout this lesson, the best teaching practices of inquiry approaches, hands-on/minds-on learning, and applications to the real world will be emphasized.


  • Participants will use skills of scientific inquiry to conduct a building activity.
  • Participants will discuss the difference between using one constraint or multiple constraints in an experiment.
  • Participants will discuss how a building activity could be integrated with another content area.
  • Participants will design and implement a classroom activity involving a building experiment.


For each pair of participants:

  • Ten sheets of 8 1/2 x 11; paper (it can be scrap paper, as long as it has not been folded in any way)
  • Ruler or meter stick
  • Two books (to be the bases for the bridge)
  • Twenty drinking straws
  • One meter of masking tape
  • Baking sheet or other large flat container
  • One small Dixie cup

For the whole group:

  • At least 100 pennies (These will be used to determine the strength of the bridge, so multiple groups can use the same pennies.)



Give each pair of participants 10 sheets of 8 1/2" x 11" paper. Ask each pair to build the tallest tower that they can, with a minimum height of 14". No other materials are to be used except the paper. The paper can be manipulated by hand; folding and ripping are allowed. Allow the participants 15 minutes to work on their tower.

When the towers are completed, measure each tower. Observe and discuss the different methods that were used to build the towers.

Assessment: The assessment should center on the discussion about the towers. Which method of building seemed to work best? What were the constraints that were given for this activity? Why should the minimum height be 14" tall?


Give each pair of participants two textbooks and ask them to space the textbooks 20 cm apart. Ask the participants to use twenty drinking straws and one meter of masking tape to build a bridge that crosses this span and can hold the most pennies. (Each end of the bridge should rest on a textbook.) No other materials can be use. Both the straws and masking tape can be manipulated in any way, but no scissors are allowed and groups cannot get extra equipment even if their equipment becomes unusable. Give each group a Dixie cup to place in the center of the bridge for the penny test. Allow the participants 30 minutes to work on their bridges.

Test the bridges by adding the pennies to the cup to see which bridge can hold the most.

Assessment: Which bridge held the most? What was difficult about this building activity? Discuss other materials that could be used for this type of activity. How could this activity be incorporated into other content areas?


  1. Call the participants' attention to the fact that the first activity had one constraint (it had to be 14 inches high) and the second activity had two constraints (it had to span 20 cm and hold the most weight). Would it have been easier to build the bridge with only one constraint? Brainstorm other constraints that individuals take into consideration when building structures.
  2. Ask: Was this activity difficult? Is there one 'correct' answer to this type of activity? How could you assess students on this type of activity?

Assessment: Monitor participants' discussion and answers to questions.


Have the participants discuss how this activity can be used in a specific content area. Ask them to design their activity, detailing the materials and constraints that would be given. (For example, a language arts teacher might assign a book about a bridge and one of the constraints would be that the student's bridge would resemble the bridge in the book.) If time allows, have the participants implement the newly designed activity and observe the participants in action.


Teaching with inquiry can be defined as giving "students ample opportunities to apply the reasoning and procedural skills of scientists while learning the principles and concepts of science along the way." This activity gives participants the opportunity to build and test several structures.

Hands-on/minds-on learning activities allow for students to manipulate materials in accordance with their individual learning styles while generating their individual ideas.

When inquiry and hands-on/minds-on learning activities are coupled with real-world situations, students see the relevance and application of their knowledge. The overall experience then becomes more meaningful for the student and enables them to think beyond their school setting.

Science Standards

NSES Content Standard A: Science as Inquiry: As a result of activities, in grades 5-8, all students should develop

  • abilities necessary to do scientific inquiry
  • understandings about scientific inquiry

NSES Content Standard E: Science and Technology: As a result of their activities in grades 5-8, all students should develop

  • abilities of technological design
  • understandings about science and technology

NSES PROFESSIONAL DEVELOPMENT STANDARD B: Professional development for teachers of science requires integrating knowledge of science, learning, pedagogy, and students; it also requires applying that knowledge to science teaching.

NSES PROFESSIONAL DEVELOPMENT STANDARD C: Professional development for teachers of science requires building understanding and ability for lifelong learnin

Best Teaching Practices

  • Hands-On/Minds-On Learning
  • Authentic Problem-Based Learning
  • Inquiry

Time Frame

This module can be conducted in 2 hours.


Gather copy paper to use for building; it can be used paper as long as it has not been folded or ripped. Looseleaf paper will not work for this activity. It may be helpful to have extra paper on hand in case a design fails during development and more materials are needed.

Textbooks work well as bases of the bridges.

Realize that these activities may be somewhat frustrating; encourage participants to collaborate, explore, and take risks.

Ask the teachers to bring their own curriculum guide or teacher's manual for lesson plan development. This activity involves the opportunity for teachers to apply the information to other subject areas.


Clean up the pennies following this activity.


This assessment can be done individually or in pairs.

Explanation of Science

Students should be provided with opportunities to discuss problems and design solutions to address issues. Opportunities to implement and evaluate designs give students the occasion to explore issues related to science and technology and to realize that science and technology are interwoven, that perfect solutions cannot be found and therefore trade-offs must occur, and that unintended benefits and consequences can occur as the results of innovations.

Science is characterized by exploration and explanation. Scientists "discover" that which can be directly observed and experienced. Science does not stop at exploration. Scientists look for patterns in their observations and propose explanations for their observations. Engaging students in the processes of building scientific knowledge by having them hypothesize, collect data, make observations, analyze their findings, and communicate their results helps them better understand the nature of science.

When engaged in an authentic activity, students can apply their knowledge to the real world. Adding constraints to an activity increases its similarity to a real-world situation and allows for further thought, discussion and imagination.


None Available for this Module


Other materials could be used for building structures (toothpicks, LEGO® or other blocks, etc.) or other types of structures (dome, tunnel, etc.) might be built. Also, discuss other constraints that could be added to the activity.

Lesson Implementation Template

Download Lesson Implementation Template: Word Document or PDF File


Be aware of the needs of diverse participants and try to pair participants' heterogeneously.


None available for this module.