Build It Strong

50-60 minutes

• Set up each team's gap ahead of time: two equal book stacks (or cups) about 20 cm apart.
• Put the load - a cup of coins or washers - at a shared testing station.
• Demonstrate once: a flat card versus a folded card, and a square versus a triangle, so students feel why shape matters.

• Count out about 20 craft sticks and a few index cards per team so everyone starts even.
• Use light coins or metal washers, never heavy objects, so a collapse is safe.

• Structures snap when they fail - keep faces back and fingers off the deck during a load test.
• If skewers are used, they are pointed; supervise closely or swap them for straws with younger students.

• Explain load and support, and how force travels down into the supports.
• Show that triangles hold their shape under load better than squares.
• Compare materials and pick a stronger shape for a weak material.

• Weight piled at one edge instead of the center - not a fair test.
• Joints taped weakly, so the structure pulls apart at a connection before the material fails.
• A flat, unbraced deck that sags in the middle.

• "Where did it bend or break first, and why that spot?"
• "What is carrying the most weight right now?"
• "Where could a triangle help?"
• "How could you hold the same weight using fewer craft sticks?"

Shorten the gap to 10-12 cm and pre-build the two supports so students focus only on the deck.

Widen the gap, ban a support in the middle, or set a material budget such as 12 craft sticks.

• Peel tape off reusable craft sticks and sort them back into a bin.
• Return coins and washers to the testing station and recycle the failed decks.