See a Need, Fill a Need Tese inventors all saw a need. Tey tried to fill that need. So did Margaret Knight. Knight worked in a factory. Te factory made flat paper


bags. Tey looked like envelopes. Tey couldn’t hold much. She saw a need for a bag with a square bottom. Tose bags could carry more food. She wanted to invent a machine that could make these bags. Knight looked at the machines in


the factory. She learned how each one worked. She learned how the machines made the flat bags. Ten she started making drawings


and models of her ideas. It took her a year to make a model that worked. Knight earned a patent. A patent is


a legal paper. It protects an invention. No one else can make or use the invention. Others must ask permission first.


The invention of the traffic light helped to save lives.


Carrying food


became easier with this type of bag.


JANUARY-FEBRUARY 2013 13


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