The back staff is a naval instrument that helps people pin-point where the sun is in the sky using the sun’s shadow.  It was made around 1585 by John Davis, he was a master mariner but he didn’t like having to use other tools were you had to look at the sun and damage your eyes.  Davis then problem solved and created a tool that could do the job.  The back staff is made so you don’t have to look into the sun, you put your back to the sun.  It is my favorite invention because me and my mom were lost at sea we could have used a back staff to find shore.