Balsa Bridge

72.6 Pounds Held--top bridge
Bridge Weight--112.4 grams

Read the Kelvin Bridge Book provided by Mrs. Pennington and write a 200+ word response on bridges and using balsa.  

Use balsa and the glue provided by Mrs. Pennington to create a bridge with the following guidelines:
  • It must span a gap of 24 centimeters.
  • It must be made only of balsa strips 1/8 by 1/8  except for one piece of wide balsa for the roadway.
  • It must be created with only wood/tacky glue and balsa.
  • It must not be longer than 36 centimeters.
  • One or two small rods must pass the width of the bridge for the testing, so you must leave space for this.
  • The bridge must support 35 pounds for 1 minute.
  • Total bridge weight has to be 60 grams or less.  

Peggy Pennington,
May 2, 2013, 9:35 AM