This is a video worksheet for students to complete while they watch the NOVA film, Lost at Sea: The Search for Longitude. This video is about John Harrison and his invention of the chronometer, which is a clock that runs accurately at sea to determine longitude in marine navigation. I couldn't find a worksheet to go with this video, so I made my own. The questions are in order to make it easier for the students, and you could cut the number of questions down if it's too much. The video is available for purchase on Amazon or free on YouTube, and lasts about 53 minutes.