Assertion: tide's period | /r/HasProperty | greater than 12 hours
Facets:
Source sentences:
text: There exist two kinds of waves: class 1 waves, (sometimes called gravity waves), labelled by positive n, and class 2 waves (sometimes called rotational waves), labelled by negative n. Class 2 waves owe their existence to the Coriolis force and can only exist for periods greater than 12 hours (or |ν| ≤ 2).