My hypothesis was that the wool fabric was going to provide the best insulation for the glass jar. The results show that this hypothesis is incorrect because the fleece fabric provided the best insulation for the water in the glass jar. Of the six fabrics I used, fleece had the best insulation, then wool and felt, cotton, denim, and last, polyester. I learned by doing this project that fleece is a better insulator than my hypothesis which was wool. This experiment also can be used to learn that fleece is the best fabric to keep you warm, especially in the winter.

Additional Information on Insulation

Insulation, use of materials or devices to inhibit or prevent the conduction of heat or of electricity. Common heat insulators are fur, feathers, fiberglass, cellulose fibers, stone, wood, and wool; all are poor conductors of heat. The use of asbestos, formerly a common insulating material, has been curtailed due to its implication in lung disease. Industrial furnaces are built of brick, witch conducts heat so slowly that a high temperature within is barely apparent in the temperature of the outer surface. Steam pipes and water pipes are commonly insulated with thick wrappings of fiberglass pulp. Since insulators prevent the flow of heat in either direction, refrigerators are commonly constructed with double walls separated by an air space (air being a poor conductor) and lined with some insulating material.

The use of double walls or hollow tiles in buildings prevents the entrance of heat and its escape. The very effective insulation in a vacuum bottle results almost entirely from the presence of a vacuum between the double walls of the inner flask. In the conduction of electricity point to point, the conductor acts as a guide for the electric current and must be insulated at every point of contact with its supports to prevent escape, or leakage, of the current. Dry air is a good insulator, or dielectric, so that conductors used for electric-power transmission require insulating material only at their points of contact with the supporting steel structures. Glass and porcelain are commonly used, molded in bell-shaped forms or in rods made up of several segments. Underground conductors are insulated with dry cotton or pulp, rubber, and bitumen. In electrical apparatus, ebonite is wildly used. Some other insulators are paraffin, sulfur, resin, and varnishes.

Since wet materials can become conductors, insulation must often be water proof. Ordinary house hold wires are commonly insulated by a thin rubber or plastic coating; the electric cables passing between houses walls frequently have in addition a metal wrapping. Depending upon the application, the insulating material may also need to be resistant to various types of corrosion resulting from exposure to salt water, oils, or other influences.