Bridge building challenge

Work in teams to build the longest bridge possible from a defined collection of common materials. Teams present their various creative solutions to solving the same problem.
Science content
Physics: Motion and Forces, Newton’s Laws, Gravity (K, 2, 6)
Lessons activity is in
  • two chairs, or a chair and table for each group to form their bridge between
  • tray or bag to contain each kit of materials
  • materials for each group (materials can be in bulk bins for students to collect, or already assembled in kits): 2 clothes pegs, 2 chopsticks, 2 pipe cleaners, 2 paper clips, 2 toothpicks, 2 labels/pieces of tape, 2 half-sheets of letter sized paper (they fit in a bag). replace any of these with other materials at hand

Tell students that they will be working in groups (of 2,3 or max 4) to build a long bridge between two chairs/a chair and desk, using the materials provided. The bridge can be as narrow as they wish (it can be for ants to cross on), but it must stay up off the ground. If you would rather not have the competitive nature of this challenge, make a scenario, such as "we will turn our classroom into a city with long bridges for ants to move between desks and chairs".
Students may only use the materials provided, and cannot get any additions/replacements. Materials can be opened up, torn or broken if the students wish.
Tell them to investigate and manipulate the materials to see their different properties and ways that they might be used. Some materials will be good for structural pieces, some will be good for fastening those pieces together, some could be used as either.

Hand out bags/trays of materials, or ask students to collect their own tray of materials from bins.
Allow 20 minutes or more for building.
Some creative ideas I have seen (pictured), usually overcoming the little amount of tape they are given (try the challenge with no tape??):
Using small pieces of pipe cleaner, or toothpicks or pieces of chopstick to attach pieces of paper together.
Opening the clothes peg wide so that it clamps onto a table edge, as well as to a piece of paper.
One end of the bridge simply sitting on a desk, using materials to keep it weighed down.

Part way through building, visit each others' bridges and ask each group present a challenge they encountered and how they overcame it, or to ask the rest of the class to help them solve it. Just as engineers share ideas to solve structural problems, students are encouraged to share ideas within and between groups.

Discussion points to bring up during sharing:
Each of the materials have different properties - some are flexible, some are strong (metals are strong and flexible, paper is light). Some can be broken apart to make them longer.
Doubling up of materials makes them stronger. This is also done in making real bridges e.g. several steel beams are strapped together to make a support.
A bridge needs two components: 1. structural pieces, which make up the scaffolding and give a bridge its length. Students may have used chopsticks, extended pipe cleaners or long pieces of paper, while the structural elements in real bridges are steel or wooden beams that are long and rigid. 2. fasteners hold the the structural elements together. Students might use bolting (e.g. weaving a toothpick through two pieces of paper), taping, or crimping (e.g. tightly wrapping a piece of pipcleaner around a chopstick or using a clothespin) - all these methods are used to make real bridges. Other methods used to fasten real bridge structures together are welding, gluing and cement. Some of the materials given to the students can only be used as structural pieces, some only as fasteners, and some as both. The students will find unanticipated ways of using the materials.

After the lesson is completed, optionally have students remake the kit bags for the next use of them.


Other ideas for building challenges, inspired by Destination Imagination challenges:
1. Build a structure as high as you can. Materials for each group: 15 sheet of paper.
2. Build a freestanding tower that is as tall as possible. Materials for each group (adapt if necessary): 10 toothpicks, 4 plastic spoons, 4 pieces of tape, 60cm string, 2 elastic bands, 6 paper clips, 2 paper cups, 2 pieces of paper, 4 chopsticks/pencils, 1 piece of foil, 4 straws.
3. Build a structure with a solid roof and at least one solid side, that one team member can get inside. Materials: 20 sheets of newspaper, 5 pieces of tape, 5 paperclips
4. Build a structure that will support as may marbles/weights as possible at lest 20cm above the table. Materials: 20 pieces of spaghetti, 3 straws, 4 toothpicks, 2cm length of clay, 2 paperclips. Scissors may be used but may not be part of the structure.
5. Build a structure that will withstand the wind from a fan. Materials: 2 paper plates, 2 sheets paper, 3 paper clips, 8 popsicle sticks, 2 pieces of tape

Grades taught
Gr 1
Gr 2
Gr 3
Gr 4
Gr 5
Gr 6
Gr 7