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.