iPod Woes

Maybe someone can tell me...I thought the iPod would re-charge if you attached the plug-in charging plug while listening to it!
Mine showed the battery icon charging, yet the iPod died on me mid-song!
Of course I had been listening to it ALL day!
Funny, now that I am not listening to it and making certain it is charging...it is so quiet in my house, except for the ticking of my clock!