01 · HOW TO PLAY

Get the drop into the drain as liquid water. Every step and every tool use counts as one move — match par for three stars.

HEAT and COLD reach the drop itself or any of its eight neighbors. On the drop they shift its state one step (ice ⇄ water ⇄ steam). On a tile, HEAT melts a whole ice block and COLD freezes a whole pool.

WATER — walks, drips down, merges into pools
ICE — floats on pools, stands on grates
STEAM — rises, drifts along ceilings
ROCK — solid
POOL — liquid merges in, ice floats
ICE BLOCK — solid until melted
GRATE — water and steam pass, ice does not
HEATER — melts or boils what rests on it
FROST PIPE — condenses steam that touches it
DRAIN — takes liquid water, swallows meltwater

02 · THE PHYSICS

Simplified for play: one tool charge moves exactly one state step, steam rises instantly and frost condenses on contact. The facts below are the real thing.

Ice is less dense than liquid water — its density drops by about 9% when it freezes — which is why ice floats.
USGS Water Science School — Water Density
At sea level water freezes at 0 °C (32 °F) and boils at 100 °C (212 °F); the boiling point drops at higher altitudes.
USGS Water Science School bookmark (GIP 219)
Melting 1 g of ice takes about 80 calories, warming that water to boiling about 100 more, and vaporizing it another 540 — vaporizing is by far the costliest step.
USGS Water Science School — Sublimation and the Water Cycle
Condensation turns water vapor back into liquid water — the opposite of evaporation. As air rises and cools, its water can condense out.
USGS Water Science School — Condensation and the Water Cycle

THAW

LEVEL SELECT

Thaw puzzle game