Why is scissors /ˈsɪz.əz/ and not /ˈsɪz.ɜ:ʳz/?

I am an English teacher, but have not studied phonetics much.

The sound əz is the same sound we find in "houses" "causes" "ages" "beaches". The dictionaries say that the word "scissors" contains the same sound – /ˈsɪz.əz/

However, I believe it should be this sound – ɜ:ʳz – which we find in "hers" "furs" "acres" "brothers" etc.

Am I missing something?

Solution 1:

However, I believe it should be this sound – ɜ:ʳz

Unfortunately, that is not how language works - vox populi, vox dei - linguists and grammarians merely record what is happening and try to explain it. They have no power to change things.

OED Pronunciation:

Brit. /ˈsɪzəz/; U.S./ˈsɪzərz/

See also "rhoticity" at https://en.wikipedia.org/wiki/Rhoticity_in_English

The upshot is that both pronunciations are unremarkable, although the movement against the "r" sound is gaining ground.