Prediction…
I predict that the foil blanket will keep the water hotter for longer, as light, shiny surfaces are known as good reflectors of heat, therefore it would keep the water hotter for longer.
The black beaker however, will cool down quicker because dull dark surface are the best absorbers and are good at emitting radiation therefore the water will loose heat quicker into the atmosphere.
RESULTS:
Foil covered beaker
Average
CONCLUSION:
From looking at my results and graph, you can see that although the average starting temperatures are slightly different, the temperature drop in the water in both of the beakers is actually the same, 26 oC. This does not prove my prediction is correct, which is that the foil beaker will radiate the heat back into the beaker, therefore keeping it hotter for longer and the black beaker will absorb the heat from the water and convect it into the atmosphere therefore making the water lose heat faster. This must mean that a few anomalies must have occurred, which I will look at in my evaluation.
However, if you look at the results table for Experiment 2, you will see that my prediction would be correct, as in Experiment 2; the temperature of the water in the foil beaker dropped 27 oC from 90 oC to 67 oC, whereas in the black beaker the temperature dropped 29 oC, from 89 oC to 62 oC. In experiment 1 the temperature drop for both the beakers is the same at 22 oC, and the temperature drop is also the same in experiment 3 at 27 oC.
EVALUATION:
After looking over my experiment I have seen ways in which to make it better and a few anomalies.
For example, one of the main problems of the experiment was that the starting temperatures of each of the experiments, the majority of the time differed between the alternative beakers and the different experiments. Although this did not change the difference in which the temperature dropped, it at once stopped the test being a fair one. I future, I will check and make sure the starting temperatures are always the same.
Also, the tops and bottoms of the beakers were not covered in the experiments, which would have affected the rate at which the heat would have escaped from the water as it could have been taken away by the air by convection. Therefore it would have taken heat from each of the beakers, which would have affected the results.
I think that the beakers were placed too close together which would have caused the heat coming off the foil beaker to be absorbed by the black beaker which maybe could have made the temperature of the water in the black beaker go up.
Also, I noticed that while we were doing the experiments, the foil on the beaker had the shiny-side, the more reflective facing outwards. As light shiny surfaces are good reflectors, this meant that the more matt surface was facing the water, and wouldn’t have been as good as reflector of heat as the light shiny side. This could have also affected the temperature difference between the two beakers. Next time I would swap the foil around.
Another reason why my experiment was not the success I hoped it would be is the time span, which I tested it over could have been too short. If I, say had tested it over a period of about 25-30 minutes maybe the difference in temperatures would be more noticeable. 15 minutes was, in my opinion too short to test how heat is lost from differently insulated beakers though radiation.
I would take all of these factors into consideration if I were to perform this experiment again.
Overall I think my experiment went reasonably well, but would have benefited greatly and proved that my prediction was right if I had taken the above factors into consideration.
