Unless that was an instruction to passing physicists?

:)

Syntax is about the rules of word form and order that you observe to be used in a language. Mostly in speech. This is about how people communicate in real life in spoken, written, and gestured words. A fertile field of learning with many amazing insights in cognition.

Grammar are the rules you learn for writing text. It doubles for helping adults to master speaking a new language.

Writing is not a natural, human language. More like mathematics or computer language. The written language needs prescriptive rules because writing words down as you say them makes for unreadable text. Grammar rules have to be explicit, simple, and few as they have to be learned and memorized by children in school. There is no way any grammar can cover even a sizable fraction of human expression.

Most people (almost all non-linguists and some linguists) make the reification fallacy: Because the word Grammar exists, there must exist a corresponding entity in language. Therefore, you should speak as you have learned to write.

As it is impossible to actually speak as you write, and incomprehensible to write as you speak, the harm of this superstition is very limited.

You may find this blog interesting: http://motivatedgrammar.wordpress.com/

It is written by a grammarian who also does not like National Grammer Day, or “prescriptivists” who insits on fixed ‘correct’ grammar.