Here's a version without the bad crop, comedy homicide, pointless circle around the punchline, and puritanical censoring

In his essay "To Tell a Chemist" (1965), Asimov proposed a simple shibboleth for distinguishing chemists from non-chemists: ask the person to read the word "unionized". Chemists, he noted, will read un-ionized (electrically neutral), while non-chemists will read union-ized (belonging to a trade union).

Good luck finding the chemistry teacher, though.

My initial thought was "would chemists theoretically be less into labor protections than plumbers"?

I guess that puts me in a third bucket.

Ah, because of the ions.

Took me eons.

If you don't think about it very hard, solidarity is basically macro ionization

Onionized

What about ChemE then? They're both. Sort of. Okay maybe they're not chemists, but... chemistry-adjacent.