Steve put two cups of tea on a table. The amount of tea in each cup was the same, but one cup was black and one cup was white. This table shows how the temperature of each cup of tea changed over 12minutes.

Question

Cup of tea Initial temperature (°C) Final temperature (°C)
Tea in the white cup 89 68
Tea in the black cup 91 70
The next time Steve drinks tea, he does not want it to cool down quickly. What should he do to minimize the rate of thermal energy transfer out of the cup of tea?
A. put the tea in the white cup
B. put the tea in the black cup
C. either the rate of thermal energy transfer is the same whether the cup is white or black

Answer 1

To minimize the rate of thermal energy transfer out of the cup of tea, Steve should consider the color of the cup. Dark colors absorb more heat and can also have different heat transfer characteristics compared to lighter colors.

In this case, the black cup (which started at a higher temperature) ended up with a final temperature of 70°C, while the white cup started lower and ended up at 68°C. The black cup appears to retain heat better than the white cup, likely because it absorbs more thermal energy from the surrounding environment.

Therefore, to minimize the rate of thermal energy transfer out of the cup of tea, Steve should choose the black cup.

So the answer is: B. put the tea in the black cup.