How is the entire noun clause used in sentence. The plan was that a visit to tide pool would be during low tide?

The entire noun clause "that a visit to tide pool would be during low tide" functions as the predicate nominative of the sentence.

Here's how it works:

* "The plan" is the subject of the sentence.

* "was" is the linking verb, connecting the subject to the predicate nominative.

* "that a visit to tide pool would be during low tide" is the noun clause that renames or defines the subject "the plan". It explains what the plan *is*.

In other words, the sentence is saying that the plan itself *was* the idea of visiting the tide pool during low tide.

Let me know if you have any more questions about noun clauses!