When to use Compound Noun and when to use Adjective Form of A Noun?

[snoob]

Can you tell me the difference between "science video" and "scientific facts" (.
Or more general: The difference between these, and when to use it:
- Compound Noun (Noun + Noun). Ex: science video, electric field, history teacher...
- Adjective Form of A Noun + Noun (Adj + Noun). Ex: scientific facts, electrical engineering...
And why not historical teacher but history teacher, science facts but scientific facts

 

[PaulMatthews]

Can you tell me the difference between "science video" and "scientific facts" (.
Or more general: The difference between these, and when to use it:
- Compound Noun (Noun + Noun). Ex: science video, electric field, history teacher...
- Adjective Form of A Noun + Noun (Adj + Noun). Ex: scientific facts, electrical engineering...
And why not historical teacher but history teacher, science facts but scientific facts

Preliminary point: A compound word is one where two bases combine to form a single word, e.g. "newspaper", "shirt-sleeve", "handshake", "lawn-mower" and so on. Your examples are not compounds, single words, but syntactic constructions where the initial word is either a modifier or a complement of the second.

The modifier or complement is generally an adjective or a noun:

"science video" (noun as modifier)
"scientific facts" (adjective as modifier)
"history teacher" (noun as complement)

We say "electrical engineering" where the meaning is 'engineering of an electrical kind', but we don’t say "historical teacher", since that would imply that the teacher is historical, not that they are a teacher of history – an important difference here !!