Alignment explains a broad spring-neap pattern, but a coast's actual water levels also depend on the shape of its bays, the seafloor, and weather. The same simplified Moon-Sun arrangement cannot tell us a harbour's tide time or height. This model compares tidal range and deliberately does not make local predictions.
Water and oceans · Discover & try
Why does the sea rise and fall?
Reading level 5 of 5 · AdvancedChange
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tidal range
The height difference between high tide and low tide.
spring tide
A larger tidal range around new and full Moon.
neap tide
A smaller tidal range around the quarter Moon phases.
Watch · Try · Explain
See how it works
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Idealised spring-neap comparison; sizes and bulges are exaggerated, with no local tide predictions.
What to look for
- The alignment of the three bodies
- The gap between high and low water
- A smaller range that still includes tides
Explain what you noticed
When does the spring-tide pattern occur?
Keep this idea: Alignment affects tidal range; coastal conditions shape local water levels.
Follow the sources
- NOAA National Ocean Service — What are tides?
- NOAA National Ocean Service — Tidal Variations: The Influence of Position and Distance
- NOAA National Ocean Service — What Affects Tides in Addition to the Sun and Moon?
Source material checked 2026-10-28. Explanations and activities by Nepedia. Agency source links do not imply endorsement.
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