Hi I'm doing an experiment that uses a GSR sensor. Though the serial port monitor works perfectly fine, my experiment requires the Arduino to run for roughly 15 minutes. Is there a way I can save the serial port data, or (better yet) save the graph?
Looks like you already found one way of saving the graph. Regarding saving the data, the most simple way is to run Serial Monitor, then when you're finished click on the output window, Ctrl + A (select all), Ctrl + C (copy to clipboard), then Ctrl + V into a text editor or spreadsheet program. There are also terminal programs that allow you to save directly to a file. You can use a spreadsheet program to make graphs from the data.
The simplest way is to get rid of the monitor and use a proper terminal programme with a proper recording facility. Even better is to send the data direct to Excel using the PLX v2 macro, if you can, and thus get all the Excel power.