Grade Level: Elementary School, Grades 1st– 6th
Related Classroom Topics: Civil Engineering, Force, Structures
Supplies needed per team:
- One sheet of 8.5” x 11” paper
- 8 Plastic straws
- 6 pieces of tape, 12” each
- Scissors (we do not provide these for liability reasons)
Supplies needed per classroom:
- One ruler to measure 12” spans and pieces of tape
- 10 penny rolls or Ziploc bags (2” x 3”) each full of 50 pennies or equivalent weight
How long it takes: About 50-55 minutes total:
· 5-10 minutes for introduction and explanation of the activity
· 25-30 minutes to build the bridges
· 10 minutes to test the bridges
· 5-10 minutes to discuss the results
Challenge:
Build the strongest bridge you can across a 12” span using the paper, straws, and tape. The bridge will be tested to see how much payload it can support. The payload consists of small Ziploc bags containing either 50 pennies or the equivalent weight.
What to do:
1. Lead a short discussion by asking the students to describe bridges they have seen. Why do we need bridges? What do the bridges look like? What are the qualities a bridge should have?
2. Explain that their challenge will be to build a bridge that can span 12” using only paper, straws, and tape. (The span can be created using desks or stacks of textbooks, whatever works in your classroom). Hold up a piece of paper and ask them how much weight they think it will hold. You can come back to this in the discussion at the end.
3. Explain that their bridge must hold as much weight as possible. The bridge will be tested to see how many weighted Ziploc bags it will hold before it collapses or a bag falls off. The bags must remain on the bridge for at least 5 seconds. If the bridge supports all of the Ziploc bags you can either end the test or find other items in the classroom to add to it until it breaks.
4. Encourage each team to think out and sketch their design before building.
5. Have the teacher divide the children into no more than 6 teams with 4 to 6 kids per team. Have one child from each team collect the needed materials or hand them out yourself.
6. Monitor the teams as they build their bridges. Offer suggestions as needed. Use your discretion in terms of handing out additional supplies. If one team gets additional supplies, offer the same to the remaining teams. Generally they want more tape. Provide a single Ziploc test bag upon request.
7. Once all the teams have completed their bridge or the time is up, start testing the bridges. Ensure the span is 12 inches. Have one of the team members place the Ziploc bags on the bridge until the test is complete. Count the number of bags each bridge held.
Follow-up Questions (feel free to add your own):
- Ask the group what influenced the design for their bridge?
- Where did their bridge first break when it collapsed?
- Are there similarities in the design of each team's strongest bridge?
- If you could change one thing to make your bridge better, what would it be?
Related topics you could discuss: Famous bridges around the world; civil engineering; engineering principles
