The overall shape of a structure determines its load-bearing strength. Engineers choose from many bridge designs because each one handles force in a different way. You can test this by building three bridges with different structural designs and placing weights on each one. The amount each bridge bends tells you which design resists force best and holds the most weight before it breaks.

Engineers choose from many bridge designs because each one handles force in a different way. Building three bridges and placing weights on each reveals how well each structure spreads a heavy load across its members. The amount of flex tells you which design resists force the best, showing that shape determines how load distributes across a structure.

Shape determines how a bridge handles force. You build three bridges from popsicle sticks, each with a different structural design, then place weights on each one and measure how much it bends using a micrometer. The amount of flex tells you which design resists force most effectively — and comparing those results shows which shape distributes weight best.