Bridges Challenge
Small bridge. Big challenge.
Design and build a balsa-wood bridge from the kit, then see how much load it carries on test day. No experience needed.
Registration opens Mon, Oct 12- Date
- Saturday, November 14, 2026
- 9:00 AM–12:00 PM
- Who
- Grades 4–12
- Teams of 1–4 · Free · Kit included
- When
- Saturday, November 14, 20269:00 AM–12:00 PM
- Where
- MOST, 500 S. Franklin St., Syracuse NY 13202
- Admission
- Free for students and families arriving before 9:30 AM
- Friday testingNew for 2026
- Friday, November 13 testing sessions for school teamsChoose Friday testing when you register. We'll contact you to arrange a time.
- Who
- Junior, grades 4–8 · Senior, grades 9–12Teams of 1–4 students. No limit on teams per school.
- Team leader
- A teacher, coach, tutor, parent or guardianOr another adult with the students' guardians' permission.
- Cost
- Free registration, free kit per team
- 1Register a teamOne adult leader registers 1 to 4 students. Register as many teams as you like.
- 2Pick up your kitOne free kit per team at the MOST front desk. Support sessions by appointment.
- 3Build your bridgeA truss bridge from the kit's balsa wood only, to the specs below.
- 4Test it on the dayInspection, a weigh-in and a load test until the bridge breaks, then a judges' score for design and build quality.
- Inspection first. Judges check the specs. A repair and supply station is on site.
- Weigh-in. Your bridge is weighed in grams.
- Load test. Load goes on a 5 cm board at the center of the deck until the bridge fails. Junior bridges are loaded from below with a hook, Senior bridges from above with a dowel.
- Efficiency. Load held ÷ bridge mass, both in grams. The lighter the bridge for the load it holds, the better.
- Judges' score. A panel of judges scores each bridge on design and build quality.
Once your team checks in, no more changes to the bridge.
- Use a truss design. The bridge spans a 200 mm gap between two test platforms.
- Roadbed 200–300 mm long, 50–75 mm wide and under 50 mm tall.
- An optional underhang may be up to 180 mm long and 20 mm deep.
- A 50 mm × 50 mm test block must pass through the bridge, with room for a 5 cm loading board at the center of the deck.
- Load is applied only to the bottom of the truss: the deck and lower chord.
- No splitting wood into layers. Laminating is for Senior teams only.
- Any glue is allowed.
- 30 half-length pieces of balsa wood
- 1 bottle of glue (⅔ oz.)
- Glue, any type, as much as you need
- Cardboard, as a building board
- Straight pins, to hold pieces while glue dries
- Single-edge razor blade or craft knife (with adult supervision)
- Waxed paper, to cover your plan as you build on it
- Ruler or other measuring tool
No wood beyond the kit's may be used. Anything not on the list is prohibited.
Collect your team’s kit at the MOST front desk Thursday–Sunday, 9:30 AM–5:00 PM. Monday–Wednesday or outside those hours, pickup is by appointment only. Need a hand with the build? Support sessions are by appointment too. For either, email eventcoordinator@most.org.
- 1st place
- 2nd place
- 3rd place
- 4th place
- Best Team Name
- 1st place
- 2nd place
- 3rd place
- 4th place
- Best Team Name
- Team Spirit & SportsmanshipAll divisions
How many students can be on a team?
One to four students. The team's division comes from its oldest student's grade: a team with anyone in grades 9–12 enters Senior, and a team of grades 4–8 enters Junior. The division also sets two build rules: only Senior teams may laminate, and Junior and Senior bridges are loaded differently.
How do we get our kit?
Tick “Request a kit for this team” when you register. Kits are ready right away, while supplies last: collect yours at the MOST front desk Thursday–Sunday, 9:30 AM–5:00 PM, or by appointment Monday–Wednesday and outside those hours — email the coordinator (see Contact below).
Can we add our own materials?
Not wood: only the kit's 30 half-length pieces of balsa may be used. You can use more glue of any type, plus cardboard as a building board, straight pins, waxed paper, a ruler and a razor blade or craft knife (with an adult). Anything else is not allowed.
What kind of bridge should we build?
A truss bridge, 250–300 mm long, that spans a 200 mm gap between two test platforms. Plans aren't required, but drawing the bridge to scale first (end view, roadbed, side view and top view) helps a lot. The manual has example truss designs.
Can we glue strips together to make thicker pieces?
Senior teams can: laminating, gluing pieces side by side into one thicker member, is allowed in grades 9–12. Junior teams glue only at joints, and strips that run parallel must stay at least a sheet of paper apart. No team may split a piece of wood into thinner layers.
Any tips for a stronger bridge?
Cut every piece so the joints sit flush before you glue. Glue that fills a gap weakens the bridge. Glue sparingly, since extra glue is extra mass. Build the two sides one on top of the other, with waxed paper between, so they match. And bend-test your strips first: use the stiffest for the longest pieces.
How are bridges judged?
Two ways: by efficiency, and by a panel of judges who score design and build quality. Efficiency is the load your bridge holds divided by its own mass, both in grams. The manual's example is a 22 g bridge that holds 42 kg, an efficiency of 1,909. A light bridge that holds a lot beats a heavy one that holds a little more.
What if we can't come on Saturday?
New for 2026: school teams can test on Friday, November 13 instead. Choose Friday testing on the registration form and we'll be in touch to schedule it.
Does an adult need to come with the students?
Yes. Every student needs an adult (21 or over) with them on the day. If the team leader is coming, they cover the whole team; if not, the registration form asks for a chaperone or an adult for each student.
Do we need to bring anything on the day?
Your finished bridge and your team number, which is in your confirmation email, for check-in. Bring every team member and adult to check-in together. The loading board, hook and dowel are provided at testing, and a repair and supply station is on site if anything breaks on the way.
What if our bridge doesn't pass inspection?
Judges check every bridge against the specs before testing. Check yours before you arrive and use the repair and supply station before you check in: once your team checks in, the bridge can't be changed. A bridge that is off-spec can still be tested, but it is not eligible for awards.