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Introduction

* Aim: * To determine which materials make the best insulators. * To determine the factors affecting heat loss from a container. * Fair Test: I must make sure that the tests are fair by being very accurate when measuring the temperatures of the beakers with boiling water in them, so that I end up with results that will indicate which material is the best insulator. In this investigation it is important that I use containers made of the same size, and same shape, with the same volume of water, at the same temperature. This is called 'controlling the variables', which will help me carry out the investigation as accurate as possible. * Theory: The four main types of heat transfer are the following: - Convection involves the movement of molecules and so it can only occur in fluids (liquids and gases), where the molecules can move within the body of the fluid. Convection currents are examples of floating and sinking. When part of a liquid or gas is made warmer than its surroundings it expands and rises because it is less dense. The air next to the icebox in a fridge is cooled and so it contracts. The cold air sinks because it is denser than the warm air below it. This movement of air is called a convection current. A dye in the form of a crystal or an ice cube can be used to see convection currents in water. - Conduction is the main way in which energy transfers take place in solids, but it also applies to liquids and gases. ...read more.

Middle

* Factors to Measure: - Temperature: For every couple of minutes I am going to measure the temperature to see the difference in temperature loss of the water. - Time: I am going to measure the time of how long it takes for the temperature to decrease, to see which material takes the longest to lose its heat energy in around ten minutes. * Trial Data (Preliminary Investigation): To achieve a good range of results, I am going to measure the temperature of hot water in a glass container without it being covered by any materials, to see how much the temperature of the water would fall every two minutes starting from 90�C. I will do the experiment twice, for the first time I am going to pour 100ml of water into the containers and for the second time I am going to pour 200ml of water. Time (min) Temp (�C) 100ml Temp (�C) 200ml Starting Temp 90 90 2 77 84 4 69 78 6 63 74 8 58 67 10 55 64 I will be timing for ten minutes, every two minutes because this provides a good range of results in the first couple of minutes in which the greatest and quickest heat loss occurs. * Apparatus: Below is a list of the equipment that I would need to carry out my experiment: * Five 200ml glass containers * Kettle * Stop clock * Five thermometers * Black paper * Silver * Bubble wrap * Cardboard * Wool * 200ml measuring cylinder * Method: 1. ...read more.

Conclusion

This was like that probably because the wool trapped the heat at that moment, and stopped any heat from flowing through for another two minutes that is why the temperature of the water at four minutes was so close to the temperature at two minutes. This result is anomalous since it looks strange when compared to others. To get more reliable results I probably should have repeated some of the tests like the 100ml test for the cardboard. I should have done all the 100ml tests of the materials on the same day and if I did the 100ml and 200ml tests of the materials on the same day then I would be able to compare the sets of results more accurately. To improve my method I think it will be best to add on it that I should repeat the experiment for the 100ml test and 200ml. As an improvement to my experiment I could have put a corkboard underneath the glass container, as this will have reduced the conduction of heat from the glass container into the table. I think I got a suitable range of results because they show how the test can be improved and what made the differences between the results. If I took more results down then I would have more points for each insulator and that would have made a better and more accurate graph. There is a pattern in my results because the results on the graph are all in a curve, and it is not only true for the range of values that I used and the pattern would continue beyond this range. 1 ...read more.

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