Question

1. Put many spaghettis into the boiling water.
2. Put much spaghetti into the boiling water.
3. Put many pieces of spaghetti into the boiling water.
4. Put many spaghetti noodles into the boiling water.
[Which one is grammatical?]

Answer 1

We wouldn't say any of those. We'd say,

Put a half pound of spaghetti into the boiling water.

Put the spaghetti into the boiling water.