All metals are good conductors e.g. iron, brass, aluminum, copper, gold, and silver. Gases and liquids are truly abysmal conductors but are also great convectors. The best insulators are ones, which trap pockets of air. If air can’t move, it can’t transfer heat as well by convection and so heat has to conduct very slowly through pockets of air, as well the material in between. This really slows it down. This is how clothes, blankets, loft insulation, cavity wall insulation and polystyrene cups.
Insulation should also take account of heat radiation. Silver finishes are highly effective insulation against heat transfer by radiation. This either works both ways, either keeping heat radiation out or keeping heat in. Examples of this keeping heat radiation out are space suits, cooking foil and Thermos flasks. And insulators, which keep heat in, would be shiny metal kettles, survival blankets, and also again Thermos flasks
Energy is transferred in many different customs. The sun emits light energy. A small percentage of this light energy is reflected back out into space but the majority is absorbed by the land and objects around us i.e.: buildings, vehicles etc. During the course of the day, this light energy is absorbed; however during the night this light energy transferred as heat energy and is emitted back out. This concept is called radiation.
The equipment that I will use for this investigation is:
How will I conduct my experiment?
I will start by obtaining a glass beaker and filling it with about 50 ml of boiling water.
I will place the selected materials into the glass beaker together.
I will then measure the temperature of the liquid (using a thermometer of course!) periodically and repeat this every minute for 10 minutes for each of my materials. I will implement this data in the form of a table. Here is how my table will be set out :
Factors that affect how well an object keeps warm :-
How I will make my test fair?
? Thickness
? Colour
? Surface Area
? Volume of water
I will keep these factors the same by using the same size and type of boiling tube. By keeping the other factors constant, I can find out the exact rate of change in temperature due to insulation.
I am also going to conduct my experiment several times in order for me to attain accurate results
Analysing evidence and the conclusion :-
When I observed my results I noticed that each of the materials were very similar as they were quite alike. This shows that my prediction was false. Cotton wool is not the best insulator, even though my results were similar.
Conclusion :-
? A slower rate of fall in temperature is noted in the case of water under insulated conditions.
? Insulation reduces the rate of heat loss.
? My conclusion did not match my prediction and therefore my prediction turned out to be false. The results show that the heat loss is at a lower rate under insulated conditions.
Evaluating Evidence: -
? My method was a sensible way of testing my prediction because I started at normal conditions and same parameters were used.
? My results are reliable because I used a thermometer and the rate of accuracy is higher and therefore taking the measurements manually. Whereas a digital thermometer could accurately record the rate of fall of temperature because it records the temperature for every second.
? I could have done my experiment in controlled conditions if possible to make my results even more reliable.
? The thermometer fell out of the uncovered tube for a few seconds and it was put back again and this could have been avoided for a more accurate result.
? My evidence supports my conclusion. I could have increased the thickness of the material used for insulation and this would give a lower level of heat loss and therefore, the difference between the temperature in the insulated tube and the uncovered tube would be more evident.
? I could repeat my experiment and take an average to increase accuracy.
? Thermometer should not touch the glass; otherwise it is measuring the temperature of the glass, not the water.
? Stirring the water would allow an average temperature to be recorded, not a local temperature.
How I can improve my experiment
There are numerous amount of ways could I improve my experiment. Firstly I use a digital thermometer because it is more accurate than an ordinary one. The thermometer being digital, records the temperature each second. This gives me a very accurate reading also. I would also repeat the experiment several times to get a broader set of results. And finally I would decrease the time over a time period of 5 minutes so I have a better idea of the rate of cooling.