Heat Insulators Experiment

           

This week, I performed an experiment on heat transfer. Before the experiment, I learned that heat is transferred by conduction, convection, and radiation. Conduction takes place when two substances are in direct contact with each other and energy transfers from molecule to molecule. Convection is the method of heat transfer in liquids and gases in which heated molecules in fluids and gases gain higher kinetic energy and move in a circular pattern called convection current. Radiation is heat transfer through space via electromagnetic waves. This week’s inquiry assignment deals with insulators and heat conduction. 

I was asked to use scientific inquiry to determine which materials are the best insulators. I began by gathering the materials: four identical mugs, four rubber bands, one thermometer, hot water, and a timer. I chose to test foil, bubble wrap, polyester material, and a cotton cloth. My initial hypotheses were that the aluminum foil would be the worst insulator since metal is a good conductor of heat and electricity, and the polyester cloth (from a scarf) would be the best insulator. Since this thin polyester scarf has kept me warm in cold weather, I thought that it may be a better insulator than the cotton wash cloth or the bubble wrap.

I poured six ounces of hot water into each mug, covered the tops with the four test materials, and secured them with rubber bands. After thirty minutes, I took the temperature of each to determine which water remained the warmest. My results were as follows: the water covered with foil was 46 degrees C, the bubble wrapped covered mug was 47 degrees C, and both the polyester and cotton cloth covered mugs were 48 degrees C. My hypothesis that the foil would be the worst insulator was correct. The bubble wrap was a bit better. I thought that the polyester covered mug would be the best insulator, but actually the cotton wash cloth was just as effective.

           
One difficulty I faced when doing the experiment was that I only had one thermometer. While I took the temperature of the first water mug, the other three mugs were cooling off. If I had to do this experiment again, I would make sure that I had four thermometers. Even though I do not think that my results would have been entirely different, they could have been more accurate.

If I were to test another material to find a good insulator, I would chose polystrene foam. I read that styrofoam (or polystyrene foam) has trapped air pockets which help insulate material. Fiberglass used to insulate homes uses the same method. Since glass and air are good insulators, small fiber of fiberglass trap air pockets which help keep homes warm.