Water Phase Diagram

Interactive visualization of water phase diagram - Explore P-T diagram, three phases, triple point, critical point, phase transitions with molecular animation

Water P-T Phase Diagram

Solid (Ice) Liquid (Water) Gas (Steam) Triple Point Critical Point

Current State of Water

Current Phase: Liquid
Temperature: 25 °C
Pressure: 1.00 atm
Density: 997 kg/m³

Phase Transition Curves

Melting (Ice-Water): Negative
Vaporization (Water-Steam): Positive
Sublimation (Ice-Steam): Positive

Clapeyron Equation Visualization

ΔH (J/mol): 6010
ΔV (m³/mol): -1.63e-6
dP/dT (Pa/K): -13.5

Phase Diagram Controls

Current State Parameters

Range: -50°C to 400°C (covers all phases)
Range: 0.001 to 250 atm (logarithmic)

Special Points

Triple Point: 0.01°C, 0.006 atm
Critical Point: 374°C, 218 atm

Animation Control

Phase Transition Paths

Phase Diagram Equations

Clapeyron Equation: dP/dT = ΔH/(TΔV)
Clausius-Clapeyron: ln(P₂/P₁) = -ΔHvap/R(1/T₂ - 1/T₁)
Triple Point: T = 273.16 K, P = 611.657 Pa
Critical Point: Tc = 647.096 K, Pc = 22.064 MPa
Water's Unique Property: Ice floats: ρ(ice) < ρ(water)
Negative Slope: dP/dT < 0 for melting (ΔV < 0)

What is a Phase Diagram?

A phase diagram shows physical states under different T and P conditions. Water's diagram has three regions: solid (ice), liquid (water), gas (steam). Boundaries are phase transition curves. Triple point has all three phases; critical point ends liquid-gas boundary. Water's unique: melting curve slopes downward (ice less dense than water).

The Clapeyron Equation

dP/dT = ΔH/(T·ΔV) describes phase boundary slopes. For water melting: ΔH > 0 but ΔV < 0, so dP/dT < 0 (unique!).

Triple Point - Unique Equilibrium

T = 273.16 K, P = 611.657 Pa. Used to define Kelvin scale.

Critical Point - Supercritical Fluid

Tc = 647.096 K, Pc = 22.064 MPa. Above: supercritical fluid.

Phase Transition Curves

Melting curve: negative slope (unique!). Vaporization: steep positive curve ending at critical point. Sublimation: connects solid to triple point.

Water's Unique Phase Behavior

Ice floats, negative dP/dT, densest at 4°C, multiple high-pressure ice phases.

Real-World Applications

Climate science, power generation, food processing, materials science, cryopreservation, refrigeration.

Factors Affecting Phase Behavior

Pressure, temperature, impurities, surface effects, nucleation, isotopic composition.