A long time ago we used small plastic tubs at home. As kids we could fill the tub completely and sit in them.
I have used bath tubs and read about bath tubs in novels (including H2G2) and have seen numerous bath tub scenes in movies or TV serials.
Why I am talking about plastic tubs and bath tubs? I don't know how it happened but just now a thought came to my mind. There was a time when the phrase "bath in tub" would be related to a kid in plastic tub. I was not using these tubs then. But I had not seen the actual tubs either.
Anyway, the thought that came to my mind was that Archimedes was not sitting in a plastic tub when he made the great discovery related to "volume of water displaced". I always imagined a grown (with whiskers) up using the kiddish plastic bathtub and found the whole incident hilarious. Of course others found it hilarious too but they were probably thinking about the guy coming out of the bath tub and running around in that state, I never reached there.
So Archimedes, sorry dood. I agree that you were using a normal bath tub and not plastic one that I had imagined till a couple of minutes ago. Were you using plastic toy ducks by any chance? Because they also featured in my imagination.. infact they were the "object" that displaced water.