What's That Round Thing?

We were going through some stuff from my school days when the blond twin picked up a record.  It was a small 45 single.  She looked at me and said, "What is this?"
The brunette twin said, "Oh, that's how they used to listen to music before. It's a record." 
The blond twin laughed and asked a few more questions.  How did you play this record? Where did you get records?  How many did I have?
I answered her questions, but all I kept thinking was "where did the brunette twin every see a record?"