Blok watches sound like a good option.
Watches
A community for watch & horology discussion.
Timex seems like the no brainer. An expedition or a weekender come in tons of colors and strap options and are pretty solid. I have a weekender I’ve traveled to 4 countries with that’s still rockin with barely a scratch
If you are in the US the citizen eco-drive bm8180 is a good small and durable analog watch. Just leave it on a shelf where it can get some daylight when not wearing and it'll just work for many years.
The invicta vintage 37071 is also small and vintagr/classic looking.
The Casio mtd1053 is 40mm and a good dive style watch. I think there is a smaller invicta prodiver quartz diver also but I'm not sure about the size (35mm or 38mm).
The 35mm escapement time king seiko homage is another dressier option.
Pulsar field watches are small and budget friendly and robust and there is one with a full lumed dial that might be cool for a teen.
The Shanghai 8120 is a small and budget friendly mechanical (handwind only) vintage/classical watch. Since it's not automatic it might not be that good of a choice for everyday wear unless he realy would enjoy winding it everyday. It might also get damaged if overwound, I don't know if the Chinese standard movement has overvond protection, i assume it doesn't.
Also some of the timex 3 hand watches tick very loud and those might be annoying in a silent classroom.
I really appreciate all this info!!!