Assuming from Table 1.1 a typical value of the modulus of elasticity of Cold water to be 2130MN / m, it is Seen that air at 100 kpa is 2130 X 1000 / 100 = 21300 times as compressible as cold water isothermally, or 15200 times as Compressible as cold water isothermally, Or 15200 times asCompressible isentropically