Thermal insulators - Sample Essay
To investigate different materials for the most effective thermal insulator for a house. Introduction Heat transfer is the gain and loss of energy. There are three ways in which thermal energy can be transferred: Conduction Convection Radiation Conduction – this is when energy travels from molecule to another. When one molecule receives energy it begins to vibrate and hits other molecules and makes them vibrate. And will spread throughout the object. Convection – this will only occur in gases and liquids.
When heat is applied to the bottom of the substance, it will heat it up. When it heats up, it will rise to the top, forcing colder areas towards the heat source and then they will receive energy and rise to the top, etc. Radiation – it travels in waves. When it hits a molecule it makes it vibrate. I will be concentrating on conduction, as this is the main way in which thermal energy is transferred lost from housing. Which means that I need something that is a bad thermal conductor (good thermal insulator) to keep the amount of conduction to a bare minimum? Plan.
I am planning to test five materials (paper, cling film, cloth, bubble wrap and plastic) and one control, three times and find the average (to ensure accuracy). Whichever material changes the temp of the water the least is the best insulator. I will wrap them around a 200ml beaker (no lid) and fill it with 200ml of boiling water. Then I’ll take the temp eleven times: once at the beginning, and once every min for a period of ten minutes. Equipment List Stop watch – 1 Thermometer – 6 200ml beakers – 6 Kettle – 1 Fair Test The following will be kept the same throughout the whole experiment: Method Time given to cool.
Equipment Conditions Also some of the variables will be need to be kept the same throughout the whole experiment: The variables The variables that will be kept the same The variables that will be changed Start temp of water Start temp of water Material (insulator) Start volume Start volume Room Temp Room Temp Material (insulator) Surface area of beaker Surface area of beaker this is a variable because it changes the amount of convection that happens. Method 1. Prepare the beakers by insulating them with the five materials (except the control) using elastic bands. 2. Put water in the kettle and turn it on. 3.
When the water is hot, pour 200ml into any 3 of the 6 (doing three at a time, gives you more control over the experiment. 4. Place thermometers in the beakers. 5. Record the start temp. 6. Start the stop watch. 7. Record the temp every min for ten min. 8. Repeat the process for the remaining three. Prediction I think that the best thermal insulator will be the bubble wrap due to the fact that it contains trapped air. Trapped air is a good insulator therefore it takes longer for energy to transfer through gasses because the molecules are further part, a vibrating molecule takes longer to hit into another molecule and make it vibrate.
The worst thermal insulator will be something that has compact molecules as it is easy for the vibrations to spread throughout. Results in degrees Celsius Material Start temp i?? C 1 min 2 min 3 min 4 min 5 min 6 min 7 min 8 min 9 min 10 min Cloth did plan to repeat the experiment three times and find the average.
However due to a lack of time this did not happen. Analysis All the materials are above the control; this gives me the impression that all the materials do have some resistance to the thermal energy that is transferring through the beaker. The graph has a negative correlation which explains, as time goes on the temperature of the water decrease. The papers final result is 68 and plastics is 67, however they both have same line of best fit, which implies to me that their results are very similar. This may well me that they are equally good insulators.
My prediction was that the bubble wrap was the best insulator because it contains a lot of trapped air. However after completing the investigation, my prediction proved to be incorrect. The best insulator proved to the paper. My only explanation to this is that when the paper was wrapped round the beaker some air became trapped between the paper and beaker and cause and insulation sufficient enough to keep the temperature of the water higher than the rest. Evaluation Although this experiment went well I felt that it could have been improved, for example.
Having the same length and width of each material would have the experiment much better in fairness. Also I was not able to repeat the experiment twice more due to lack of time which severely affected the accuracy of the results and investigation. Finally having a thermometer for making sure the room temp stays the same I think that the method was fine and has no problems of any sort except one: testing the room temp and making sure it stays the same. Conclusion To conclude, this experiment was seemingly fair, however there is a margin for improvement.
The paper was the best insulator however I think this was an accident due to the trapped air. I now know that the closer the molecules in an object the better the object is at conducting energy. Which means any thing with trapped air would be a sufficient insulator. This is why they use double glazed windows as an insulator. Show preview only The above preview is unformatted text This student written piece of work is one of many that can be found in our GCSE Electricity and Magnetism section. Download this essay Print Save Here’s what a teacher thought of this essay 4 star(s).