insulation materials

[matty22]

can anyone tell me the order of these materials in terms of their thermal insulation properties;
ceramics
wood
metals
plastics

[Skids]

Simple test, obtain some items made of these materials, easy to find around the house (don't forget, glass is ceramic). Try not to use items that have been coated. Place them in a room and allow them all enough time to reach room temperature. If you've already got those materials in the same room, ideal. Place your bare skin on each material in turn allowing your skin to return to normal temperature between each touch. The one that feels the coldest, usually metal, is the worst thermal insulator. And it goes on in that order. You should find that ceramic is the best insulator (there's a reason the Space Shuttle has ceramic tiles covering it's underside).

The items are all the same temperature but the metal feels coldest because it is an efficient thermal conductor and is really good at removing the heat from your skin thus making your skin feel cold.

[scotstone]

The thermal insulation property of a material can be quantified by reference to its coefficent of thermal conductivity K (W/m/K). The lower the number the better it is as an insulator. So for the four materials you specify:-

wood.......0.12

plastic (polythene)... 0.5

ceramics.......1.0

metals.....14 - 430

For a fuller list see here

[heathfield]

On insulation, a Norwegian housebuilder told me that 3" fibreglass = 18" solid wood = a metre of concrete.

[spacechimp]

Why does he use a strange cocktail of imperial and metric measurements?

[stanleyman]

It depends on what type of ceramic, you can get ceramic insulation board but otherwise and generally it would be: wood, plastics, ceramic, metal.