Score: 0
Ports 0/3
Time: 90
Drag Luna to raise the tide. Match every buoy contract!
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About Tidal Proof

Drag the Moon around a water-covered Earth and solve real tide puzzles in this free online ocean tides game about differential gravity, spring tides and the two-bulge mystery.

Tidal Proof is a free online ocean tides game where you drag the Moon around a water-covered Earth and serve harbor contracts that demand high tide, low tide or dead-calm water at specific ports. It is built on the most mis-explained phenomenon in popular science: the ocean does not have one bulge facing the Moon, it has two. The Moon's gravity pulls the near-side water hardest, the solid Earth a little less and the far-side water least, so relative to the planet the sea stretches into an oval with highs on both the near and far sides.

Every mechanic maps to real tidal physics. Lunar tidal force falls off with the inverse cube of distance, which is why the Perigee Pearl sends Luna closer and multiplies the bulges. When Sol rises mid-run, its tidal field is exactly 46 percent of the Moon's, the true solar-to-lunar ratio that follows from mass over distance cubed. Aligning the two bodies stacks the bulges into spring tides at syzygy, while squaring them off at quadrature cancels most of the range into neap tides. Water beads lag behind the equilibrium shape because real oceans cannot respond instantly, and storm surges stack on top of the astronomical tide exactly as they do on real coasts.

This matters because tides run the world's coastlines. The roughly 50-minute daily drift of high tide follows the Moon's orbital advance, amphidromic points anchor near-tideless spots like Tahiti and king tides at perigean syzygy already test seawalls from Miami to Mumbai. Understanding the two-bulge differential model turns tide tables, flood forecasts and lunar calendars from trivia into predictable physics.

Key Science Concepts

What You'll Learn

Grade Level: Middle School, High School

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How to play

  1. Drag Luna Drag anywhere to swing the Moon around Terra. Water bulges BOTH toward Luna and on the far side: two highs, two lows.
  2. Read the Buoys Each port calls HIGH, LOW or CALM. Park a bulge for HIGH, a low-water notch for LOW and a flat node for CALM.
  3. Mind the Lag Water is sluggish. The sea takes a moment to follow Luna, so lead your moves instead of chasing the gauge.
  4. Work With Sol Mid-run the Sun adds its own weaker bulge pair. Line Sol and Luna up for spring tides or square them off to flatten the sea.
  5. Survive Surges Storm surges pile extra water on one port. Drag a tidal low onto that port or tap the safety gauge to slam the storm gates.
  6. Chase Perigee Tap the Perigee Pearl to pull Luna closer: tides grow fast, scores multiply and floods get risky. Greed is a mechanic.

Frequently asked questions

Is Tidal Proof free to play?
Yes. Tidal Proof is completely free to play in your browser. There is no download, install or account needed.
What grade level is Tidal Proof for?
Tidal Proof is designed for Middle School, High School students and works well as a classroom activity or homework.
Does Tidal Proof work on phones and tablets?
Yes. Tidal Proof runs in any modern browser on desktop computers, Chromebooks, tablets and phones in landscape mode.

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