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Glass is far inferior to paper, plastic and Styrofoam in terms of insulation. Thermal conductivity in terms of BTU/(feet - hour - degrees F) is 1.82 for glass, 0.09 for paper, 0.06 for Styrofoam. The conductivity of plastics varies depending on the materials: for polypropylene and polycarbonate, the thermal conductivity values are 0.69 and 0.35, respectively.
Below the lambda point, however, helium does not boil, and it expands as the temperature is lowered further. Helium I has a gas-like index of refraction of 1.026 which makes its surface so hard to see that floats of Styrofoam are often used to show where the surface is.