I was going to say something about how you needed to know what DNS is to know how URLs work and how all this is easily teachable at the high school level, but I realized I'm just out of touch. Amend my comment to say that the previous poster's classmates can't tell apart a search bar and a URL bar either.

I also question if you need to know what DNS is to know how URLs work. "This name is how your computer finds the website you are looking for" is sufficient for some level of knowing what a URL is and how it works.

And URLs, canonically, don't require DNS to function.