A 1/8 note in 4/4 is the exact same length as a 1/8th note at 5/8, provided the tempo is the same.

Cool, thanks Tarekith - so th etime signature just tells us how many bars and measures...

Ta!

Yeah, the time signature just tell you the timing 'base' and most common divisions (more or less). The tempo and note divisions (1/8, dotted 1/4, whole note, etc) determine the actual length of each note.