How do I Make a Strong Expansion Bridge Out of Toothpicks?

A strong expansion bridge made from toothpicks uses flat toothpicks in the construction process. The toothpicks are glued together in a brick fashion for the road surface. The brick fashion of gluing items together looks like a brick building. The first row of toothpicks are placed end to end. The second row of toothpicks overlaps the first row so the middle of the toothpicks are over the joining ends of the toothpicks immediately beneath them. The supports are built using triangle shaped supports.

Things You'll Need

• 2 boxes flat toothpicks
• Wax paper
• Ruler
• Pencil
• Scissors
• White glue
• Hot glue gun
• Hot glue sticks

Instructions

1. Place a 12 by 18-inch piece of wax paper on a flat stable work surface. Measure, mark and cut 16 toothpicks in half. Set them aside.

2. Place eight flat toothpicks end to end in a horizontal line. Start at either end of the row and place a half a toothpick directly on top of the first row of toothpicks. Place seven flat toothpicks end to end in a horizontal line directly on top of the first row. Repeat the process until 32 rows of toothpicks are stacked like a brick building to create the toothpick road.

3. Cover the 32 rows of toothpicks with a coat of white glue. Squeeze the white glue from the bottle in vertical lines. Allow the glued toothpick road to sit until dry. This will take approximately three to four hours.

4. Place a 12-by-12-inch piece of wax paper on a flat stable work surface.

5. Lay one toothpick on a vertical plain. Lay 31 toothpicks next to the first toothpick on a vertical plain. Make sure all edges are touching. Squeeze white glue across the toothpick panel in horizontal lines. Cover the entire panel. Place a toothpick across the glued panel from the top left corner to the bottom right hand corner. Repeat the process for a total of nine panels. Allow the toothpick panels to dry. This may take up to four hours.

6. Place a 12 by 18-inch piece of wax paper on a flat stable work surface. Glue together 45 right triangles using three toothpicks per triangle. Put a drop of white glue on each point to hold the right triangles together. Allow the glue to dry. This may take up to two hours.

7. Place eight right triangles side by side making sure the bottom of the triangles are on a horizontal plain. Turn seven triangles upside down so the point is on the bottom. Place the upside down triangles between the first eight triangles. Glue the triangles together using white glue. Repeat the process for a total of three pieces. Allow the glue to dry. This may take up to two hours.

8. Glue the nine panels of 32 toothpicks together to form three right triangles. Stand three panels on their edge. Connect the three panels together to form the right triangles. Use a hot glue gun. Repeat the process to create two more panels.

9. Glue the toothpick road to the three 32 toothpick paneled right triangles. Squeeze hot glue on the flat surface of one right triangle. Center the triangle in the middle of the toothpick road. Immediately place the hot glued surface against the toothpick road. Repeat the process with the remaining two panels placing one on each end of the toothpick road.

10. Flip the toothpick road over so the three right triangles are on the bottom. The right triangles form the base of the bridge.

11. Glue the three triangle panels together to form the top of the bridge. Place a triangle panel on a horizontal plain. Stand a triangle panel on edge and place it along the top edge of the flat panel. Make sure to line up the two ends. Glue the panel into place with a hot glue gun. Repeat the process with the bottom panel. Hold each panel for 30 seconds to ensure the hot glue is set.

12. Flip the triangle panels over so the open side is on the bottom. Place the open side of the triangle panel on the brick toothpick road surface. This structure is the sides and top to the bridge. Glue the triangle panel into place. Squeeze a line of glue along each triangle panel edge. Allow the glue to dry before moving.

References

• Scholastic: Suspension Bridges
• Worsley Schools: Bridge Building Using Toothpicks