01 ยท Ship on the Horizon: Use the slider to see how, as the ship moves farther away, the curvature formula (distanceยฒ รท 2R) causes the hull to disappear first while the mast stays visible longer.
02 ยท Eratosthenes' Experiment: Recreates the ~240 BCE experiment that estimated Earth's circumference from the difference in shadow angles between Alexandria and Syene (at 7.2ยฐ, the result comes close to the actual value of 40,075 km).
03 ยท Lunar Eclipse Shadow: Compare a rotating sphere and a rotating disk โ the sphere's shadow is always a circle at any angle, while the disk's shadow changes shape depending on the angle.
04 ยท Day and Night: Move the time slider over the world map to shift the sun's position and watch the day/night boundary line move accordingly.
This is a live earthquake visualization dashboard connected to the USGS earthquake API (no key required, CORS-enabled). Filters: Combine time range (Past Hour / Day / 7 Days / 30 Days) with minimum magnitude (All M1.0+ / M2.5+ / M4.5+ / Significant), mapped directly to USGS's actual feed URLs ({threshold}_{period}.geojson). World Map: Each earthquake is shown as a dot sized and colored by magnitude (green โ yellow โ orange โ red โ purple). Clicking a dot auto-scrolls to it in the list below. Magnitude Distribution: A bar chart showing how many quakes fell into each magnitude range (<2 / 2โ3 / 3โ4 / 4โ5 / 5โ6 / 6+). Depth vs. Magnitude: A scatter plot showing the relationship between magnitude and depth (deeper quakes plot lower, stronger quakes plot further right). Recent Earthquakes list: Sorted by magnitude, showing location, depth, and time elapsed, with click-to-highlight on the map. Summary cards: Total quake count, largest magnitude, average magnitude, and average depth.