- Why was the calorimeter insulated? In the set of apparatus , the little bottle inside is made of aluminium and the bottle is surrounded by the foam and the plastic cylinder-shaped equipment. Since the plastic and foam both can effectively avoid the heat from losing, the calorimeter can be insulated.
- Why do you think the the heating apparatus was coiled? (wound in circles). Because it can make the speed of the heat passing through slower, in order to make the temperature not to goes up so fast.
- Why do you think the vessel we held the water in was made of aluminium (Al) and not some other material. Because differ from other metal, aluminium has a very good hermal conductivity, which can make the experiment more accurate since the temperature of the aluminium bottle would affect the change of water temperature so little.
- If you had to pick another material to make the vessel out of what would it be? and why? I would use copper. Because it also has a good hermal conductivity that could make the experiment more accurate.
- Would you expect the value we measure for the SHC of water be exactly 4200 J / kg / K? Justify your answer. I wouldn't expect the value we measure for the SHC of water be exactly 4200J/kg/K. Because even though we keep all our apparatus settled perfectly, there is still some heat that will miss all the way since the apparatus is not completely sealed. Our group get the capacity of water by c=Q/m△θ. Since Q=IUT=1.5A*3V*7.47*60s=2016.9J, we get the Q. Then from the equation I wrote above, c=2016.9J/ (167.5-30.1) x10^-3kg*2K=7339.52J/kg (K). So we can see that the result we get is a way too different from the standard one.
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Inhibitory effect of black tea on the growth of established skin tumors in mice: effects on tumor size, apoptosis, mitosis and bromodeoxyuridine incorporation into DNA.
By Y P Lu, Y R Lou, J G Xie, P Yen, M T Huang and A H Conney Abstract: The authors were trying to find out the inhibitory effect of black tea on the growth of established skin tumors in mice: effects on tumor size, apoptosis, mitosis and bromodeoxyuridine incorporation into DNA. There are totally two experiments on studying this topic. Mice with established papillomas were treated with black tea or decaffeinated black tea as the sole source of drinking fluid for 11-15 weeks. They repeat this experiment for four times and then found out that in the experiment of black tea inhibited the growth of papillomas has an average of 35%, 37%, 41% and 48% respectively, while the decaffeinated black tea inhibited papilloma growth by 27, 14% and 193% respectively. In the other separate experiment, they use the ultraviolet B light to treat the mice for 22 weeks, then waited for another 13 weeks to treat those mice with black tea as the drinking fluid for 11 weeks. It turned out that the tumor growth was inhibited by 70%. And the results “indicate that oral administration of black tea to tumor-bearing mice inhibited proliferation and enhanced apoptosis in nonmalignant and malignant skin tumors.” In the journal report, the authors reported the data and phenomenon very briefly but also clearly. I think one of the biggest characteristics of their language using is they can perfectly combine the data and the words into a kind of scientific telling way, which is completely different from the way we use to tell a story or write an article. For instance, when they talk about the material they used in the experiment, they will include the unit as well as the type of the material. What’s critical is, the sentences in their journal report are more official and precise. They use very professional and technical terms to illustrate the journal report, which makes this journal report seem more standard than ours. They actually communicate the results based on the data they got from the experiments, just like us, and then define whether their assumption is right or wrong. The using of words is all very clear and concise, which is different from an article writing, but it is not very hard to understand. So from this journal report, I think I learned how to write more formal experiment report with more scientific and professional terms. I think I need to work on the terms of things we would use in the experiment; this is one of the biggest parts that make the report look so professional. |