Watch a real physics model of an iceberg: Archimedes' principle keeps about 90% of its bulk underwater, ocean currents and wind steer its drift track, and rising water temperature accelerates waterline erosion, underwater melt and calving until the berg eventually disappears.
Archimedes' flotation principle (ice density ≈ 0.917 g/cm³ vs seawater ≈ 1.025 g/cm³), vector addition of current and wind drift, and temperature-dependent melt and calving.
Adjust the current and wind sliders to change the drift track and vectors, raise the water temperature to speed up melting, and pick a starting size — watch the info bar for live drift speed, elapsed days and remaining volume.
The famous "tip of the iceberg" idiom is physics, not exaggeration — with about 90% of the mass submerged, ships must give icebergs an enormous berth even when only a small white peak is visible.
An iceberg floats because ice is roughly 8% less dense than seawater. Archimedes' principle says a floating body displaces its own weight in fluid, so the submerged fraction of the ice equals the ratio of the two densities — about 0.917/1.025, or 89.5%. That leaves only around 10.5% of the iceberg, the freeboard, visible above the waves, which is why so much of a berg's true size and hazard lies hidden beneath the surface.
An iceberg's drift track is not simply downwind: because the bulk of its mass sits in moving water, ocean currents dominate its motion, while wind acts only on the small area above the waterline and contributes a much smaller push, often at an angle to the current. Meanwhile warmer water accelerates two melt processes at once — faster erosion right at the waterline, which can undercut the ice and create unstable overhangs, and slower bulk melting below the surface. When an overhang becomes too unstable, a chunk calves away as its own smaller iceberg. These processes matter well beyond curiosity: they govern shipping hazards in iceberg alleys, contribute to global sea-level rise as land ice enters the ocean, and feed back into climate models through freshwater and albedo changes.
Why is about 90% of an iceberg submerged?
Archimedes' principle states that a floating object displaces a volume of fluid whose weight equals the object's own weight. Ice has a density of about 0.917 g/cm³ and seawater about 1.025 g/cm³, so the submerged fraction equals that density ratio, roughly 0.895, or about 90%. Only the remaining 10% or so, the freeboard, sits above the waterline.
Why does the ocean current dominate over the wind?
Because roughly 90% of an iceberg's mass is underwater, moving currents exert force over a much larger area than wind can on the small exposed tip. As a result icebergs mostly follow the current, with wind adding only a small correction — real-world studies estimate the wind contribution at just a few percent of wind speed, sometimes deflected at an angle from the true wind direction.
Why does warmer water melt icebergs differently at the waterline than underwater?
At the waterline, wave splash, warmer surface water and air exposure combine to erode ice faster, often carving an undercut notch beneath the surface. Below the waterline the surrounding seawater is usually cooler and more stable, so bulk melting proceeds more slowly and steadily. Both rates rise with water temperature, but the waterline effect is typically the faster of the two.
Calving is when a chunk of ice breaks away from a larger iceberg (or a glacier) and becomes its own separate piece. It commonly happens after waterline erosion undercuts the ice enough that an overhang becomes structurally unstable and shears off, producing a smaller fragment that then drifts and melts on its own track.
Current speed and direction set the dominant ocean-current vector that carries the iceberg; wind speed and direction set a much weaker secondary push; water temperature drives both waterline erosion and underwater bulk melt; and starting size picks the initial radius of the main berg before the run begins.
Icebergs that calve from land-based ice sheets and glaciers carry ice that was previously stored on land into the ocean; once that ice melts, it adds to global sea level in a way that sea ice melting alone does not. Freshwater released by melting can also alter local ocean salinity and circulation, and changing ice cover affects how much sunlight the polar oceans reflect versus absorb, feeding back into broader climate patterns.
The 89.5% submerged fraction comes directly from real ice and seawater densities, and the melt-rate formulas and current-dominant drift are grounded in real oceanography. The exact numeric melt-rate curve, the wind-deflection angle and the calving probability are simplified, clearly-labelled approximations chosen for a smooth, readable simulation rather than a research-grade forecast model.