Equipment
Two 300ml beakers
Two thermometers
A heat proof mat
Eight strips of polystyrene insulation
Two polystyrene lids
A kettle or source of water over 80°C
Two stopwatches
Investigation to See How Insulation Affects Heat Loss
Method
We will boil the kettle then pour it in a measuring cylinder to get 125ml then pour it into the beaker, add the thermometer and wait until the temp is at 70°C and not rising then start the timer for five minuets. At five minutes we will take the temperature and work out the heat loss. After that we will repeat the experiment to get an average. To make sure the results are accurate we will measure the water the look at the reading from the same level.
Results
The results were measured from 70°C and we measured the heat loss.
I have highlighted two results that seemed slightly out of sequence. These results seemed out of sequence because the results had steadily declined then the temperature jumps up by 2½ °C from 8°C to 10½°C so that affected the average.
Investigation to See How Insulation Affects Heat Loss
Conclusions
The first graph had one odd result, which was experiment two insulation three. The result was 10½°C which kind off made its line and the averages line on the graph look out of place. On the whole the graph slowly drops then at three layers of insulation shoots up by about two degrees it then starts declining again. The second graph, which had a lid, declines steadily and there doesn’t seem to have any odd results.
The first set of experiments (without lids) lost a lot of heat through convection because there is a lot of hot water exposed to the cooler air. The cooler air heats up and then rises drawing in more cool air to the hot water, which is giving of lots of energy heating the cool air that keeps circulating until the hot water is cool. The second set of experiments (with lid) lost quite a lot of heat at the beginning when there wasn’t much insulation but once it got to about two layers the water was only losing about 4°C . At the begging the water was losing quite a lot of heat through convecion and radiation but as the layers built up the heat loss got suprisingly low, in one case only a loss of 2°C.
My predicion was roughly accurate with the idea about the lid making a lot of difference and the insulation not making much difference.
Investigation to See How Insulation Affects Heat Loss
Evaluation
My results were not very accurate on the first graph but they improved on the second graph. There was one odd result which I cannot explain but it may have been something to do with classroom temperature or a missread thermometer. We had two problems with our method which were, when you poured the water in to the beaker you had to wait for the temerature to drop to 70°C before you could start the stopwatch another problem was that we couldn’t get the lid to sit properly on the beaker. We started the experiment only intending to mesure the temperatur difference for without a lid, but then dicided to do the experiment with the lid aswell so we could see how much convection made a difference.
If I were to do the experiment again I would do the amount of insulation to eight to see where it stoped making a difference I would also try to measure out the hot water more acurately, also I would start the stopwatch at 80°C.