Investigation into the Effectiveness of Insulation at Preventing the Loss of Thermal Energy from the Home.

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Investigation into the Effectiveness of Insulation at Preventing the Loss of Thermal Energy from the Home

        

Aim

        I intend to find out which insulation is most effective at preventing thermal energy transfer in the home and also which is more cost-effective. I.E. which costs less to buy but makes a larger reduction in your heating bill.  

Introduction

        

        Thermal energy is usually transferred by:-

Conduction:

        This is where thermal energy is conducted through a material. It does this because on one side of the material the air is hotter than on the other side. So, the thermal energy is conducted from an area of warm air to an area of cooler air. Materials that are good electrical conductors also tend to be good thermal conductors, like; Gold, Silver and copper. These will all readily conduct thermal energy as well as electrical energy. Materials like wood, that don’t conduct electricity, are also poor conductors of thermal energy.

Evaporation

        This is where the molecules of water that are hotter than the air outside the water rise up out of the liquid as a gas. These molecules take some of the thermal energy of the liquid with them so, evaporation can cool down the water. This also work on our body, as we sweat and the sweat evaporates our body is cooled by the evaporation because the thermal energy of our body is taken in the molecules of sweat.

Convection

        This is where the hotter water molecules of water will rise up to the top of the container and the cooler molecules sink to the bottom. This happens because as molecules become hotter the also become less dense so they will rise to the top, and the cooler particle will sink to the bottom to take their place. The heat energy from the hotter molecules at the top will escape by evaporation in a liquid. This does not only happen in liquids, it also happens in air so the majority of the thermal energy will be lost from the top of the container or through the roof of the house.

Radiation.

        This happens when the molecules with a lot of energy pass their energy on to the molecules next to them. Because when molecules have energy they vibrate, this is how the energy is transferred, through vibrations. For heat to radiate it does not need to be in contact with matter, as thermal energy can be radiated through a complete vacuum. A good example of this is how the thermal energy from the sun is radiated to earth through space.

These processes are likely to all happen simultaneously but one of them will cause a greater exchange of thermal energy in each experiment. For example, it the top of the container is covered evaporation is less likely to make a great difference than if it is uncovered.

Because I am investigating the amount of thermal energy lost under different insulation conditions, this can be the only factor that I can change. Other factors that could change the outcome of my investigation are:-

  •   Temperature of water at start of each experiment (Water may cool faster at higher temperatures that at low temperatures).

 

  •   Volume of water in the container (if there is more water it may take longer to cool than if there is a smaller amount).
  •  What the container is made of (if it is shiny metal  the heat will not be radiated as easily as if it is a matt black surface, also if it is a glass container heat will not be conducted as easily through thicker glass so the beakers need to be the same. Also the manufacturers of the beakers should be the same because different manufacturers may use different property compositions which could affect the radiation or conduction aspects of the experiment).
  •   The pressure of the experiment (at a higher pressure water may cool less quickly than if it was a lower pressure because the high pressure air causes the molecules to have more energy, thus they will be hotter so stay hotter for longer. The experiments will all be carried out at room normal pressure (100 000 Pa) so there will be no change in he pressure).
  •   The room temperature (these experiments will depend greatly on the environment in which they are carried out. If the air is the same temperature as the water there is nowhere for the thermal energy of the water to go so It will stay at that temperature. Conversely, if the air is a lot colder that the water the thermal energy will escape a lot quicker than normal. My investigation will be carried out always in the same room and mostly on the same day so the difference in room temperature will be limited to around 1o – 2o).
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        I will investigate the effectiveness of different types of insulation in different parts of the home. For floor insulation I will use a foam sheet, about 1cm thick. This will be a good insulator because it has a lot of air bubbles. These air bubbles contain air that is at room temperature so when a beaker of hot water is place on it the air inside the foam will take the heat and store it there, close to the beaker so it will, theoretically cool less quickly. I will use the same foam to simulate the loft insulation but it ...

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