Chemical substance with Chemical Formula: H₂O.

In narrow meaning it defines liquid form of water to discriminate it from ice and vapor which have the same molecular formula.

It is transparent, tasteless, odorless, and nearly colorless chemical substance,

It is the main constituent of Earth's streams, lakes, and oceans, and the fluid of most living organisms.

Dynamic properties of water
Water Density	Water Formation Volume Factor	Water Compressibility	Water Viscosity

Temp., °C	Dynamic Viscosity, cP	Change in viscosity with pressure, ps	Compressibility, GPa^-1 a		Density, kg m^-3 a	Speed of sound, m s^-1	Specific heat, J mol^-1 K^-1		Thermal expansivity, 10^-3 K^-1 a	Vapor pressure, kPa	Molar volume, cm^-3
Temp., °C	Dynamic Viscosity, cP	Change in viscosity with pressure, ps	β_T	β_S	Density, kg m^-3 a	Speed of sound, m s^-1	C_P^a	C_V	Thermal expansivity, 10^-3 K^-1 a	Vapor pressure, kPa	Molar volume, cm^-3
-38^e			1.1581	0.8023	968.1	1135	108	75^c	-2.963	0.016^f	18.609
-30	8.989	-30	0.8079	0.7109	983.9	1196^b	90	79.19^c	-1.400	0.051	18.311
-20	4.473	-12	0.6425	0.6175	993.6	1277^b	80.2	77.08^c	-0.661	0.126	18.132
-10	2.668	-5.4	0.5583	0.5531	998.1	1346^b	77.2	76.47^c	-0.292	0.287	18.049
0	1.792	-2.5	0.5089	0.5086	999.8	1402	76.01	75.97	-0.068	0.611	18.018
10	1.307	-1.0	0.4781	0.4776	999.7	1448	75.57	75.49	0.088	1.228	18.021
20	1.002	-0.4	0.4589	0.4559	998.2	1483	75.38	74.88	0.207	2.339	18.048
30	0.797	-0.05	0.4477	0.4410	995.7	1510	75.30	74.17	0.303	4.247	18.094
40	0.653	0.04	0.4424	0.4312	992.2	1530	75.29	73.38	0.385	7.385	18.157
50	0.547	0.08	0.4417	0.4253	988.0	1543	75.33	72.53	0.458	12.353	18.234
60	0.467	0.11	0.4450	0.4229	983.2	1551	75.39	71.64	0.523	19.947	18.323
70	0.400	0.14	0.4516	0.4230	977.8	1555	75.49	70.71	0.584	31.202	18.425
80	0.355	0.17	0.4614	0.4258	971.8	1554	75.61	69.77	0.641	47.415	18.538
90	0.310	0.19	0.4743	0.4309	965.4	1550	75.76	68.82	0.696	70.181	18.663
100	0.283	0.20	0.4902	0.4382	958.4	1543	75.95	67.89	0.750	101.325	18.798

^a Equations generating the specific volumes, specific isobaric heat capacities, thermal expansion coefficients and isothermal compressibility coefficients over a range of temperatures and pressures are available

^b Calculated using the equation u² = 1/β_Sρ where u is the speed of sound (m s^-1), β_S is the adiabatic compressibility (Pa^-1) and ρ is the density (kg m^-3).

^c Calculated using the equation where T=temperature (K), V=molar volume (m³ mol^-1), α=thermal expansivity (K^-1) and β_T=isothermal compressibility (Pa^-1).

^d Calculated using the equation where α=thermal expansivity (K^-1), T=temperature (K), ρ=density (kg m^-3), and C_P=isobaric specific heat (J kg^-1 K^-1). κ_Smay also be calculated by β_S=β_TC_v /C_p.

^e Data is calculated from the supercooled water equation of state

See also