Just recently I wanted to show my kids the 5.25" floppy disk - I had a small stack somewhere, but could not find it. I have finally found an 3½" floppy and have shown it to my kids (14 y.o. max). Evidently they never used such a thing, but I was genuinely surprised they didn't even know what it was. After a considerable amount of time one of my daughters hesitated but said something like: "Wasn't it like old USB stick thingy?". Given they have no USB stick either that's not bad, I guess. Then I proceeded to explain that a floppy disk is pictured on Save buttons - you just had to see their faces, it was a moment of the big revelation.