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Guided path
No visible curvature
From horizon intuition to measurable hidden height
Start with the most common naked-eye challenge, then move into numbers you can check with a calculator or shoreline observation.
5 steps · about 27 minutes total
- Step 1Debunk~4 min
Horizon rises to eye level
Why a near-level horizon at low height does not rule out curvature.
Open debunk - Step 2Debunk~5 min
No visible curvature
Hidden height, horizon distance, and when the arc becomes measurable.
Open debunk - Step 3Tool~4 min
Curvature Calculator
Compute horizon distance, dip angle, and hidden target height for your own numbers.
Open tool - Step 4Experiment~6 min
Shoreline hidden height
Field-style check for bottom-first disappearance and elevation recovery.
Open experiment - Step 5Experiment~8 min
Rainy Lake curvature field test
Named Bislin-style protocol with waypoint preset, field log, and predict-vs-observe checks.
Open experiment