Which episode does a Friends scene belong to?

I am trying to place a scene in Friends so I can use the episode for a school project, but I can't seem to place it. Basically, it revolves around Joey not understanding anything that the rest of the group discusses. There are a few flashbacks that occur with examples of times when Joey nods along and agrees with the conversation, but then Du hear him say in his mind that he has no idea what is going on. I remember one of the examples was Ross bringing up the Constitution and Joey saying to himself that he didn't know what that was...

Does anybody know which episode this is from?