• How does the number of triangular supports affect the amount of weight it can hold?

• Does using a truss design make a popsicle stick bridge hold more weight than a beam design?

• How does the shape of the beam (flat, folded, or curved) affect the bridge’s strength?

• Does adding cross-bracing increase a bridge’s stability?

• What is the strongest material we have to make a bridge from.

Investigable questions can be 

answered with experimentation.

• Why are triangles used in bridge designs?

• Why do some bridges collapse under heavy loads?

• Why are suspension bridges able to span longer distances than beam bridges?

• Why are some bridge designs stronger than others?

• Why are bridges important in society?

Non-investigable questions ask for explanations, background knowledge, or big ideas that cannot be tested directly. It is the big concepts behind things.