not sure I believe you wrote:
I want to introduce you to something called the metric system.
No scientist or science class will use the old measurements unless they are pointing out silly they are in comparison.
That said, still a bit shocking someone wouldn't know this, though I'm not sure I believe the story.
I'm not shocked. I have a PhD in math and it's only since I got interested in cooking that I learned all the conversions for volume in the US Customary system. The system is ridiculous. Only trivia nerds or bartenders could tell you how much is in a dram or a gill, for example.
I know that oz and cups are far more common, but 99 out of 100 Americans couldn't tell correctly give you the size - in any measure - of an acre, or, how many yards are in a mile even. You'll hear people refer to a bushel or a peck, but, maybe aside from farmers, very very few people could tell you how much they actually are.
It will be a very good day when the US finally joins the rest of the planet and adopts the metric system.