Passage III
In an experiment to study the effect of circulation on ice formation in water, 2 identical insulated containers without lids (Tank X and Tank Y) were each fitted with 2 thermometers as shown in Figure 1. A pump was mounted on the base of Tank X. Each tank was filled with 20 L of 14°C water. Both filled tanks were then placed in a temperature-controlled freezer set to -12°C, and the pump was switched on, circulating the water in Tank X. The temperature from each thermometer was recorded every hour for 30 hours (see Figures 2 and 3).
13. Compared to the water at the top of Tank Y, the water at the bottom of Tank Y took approximately how many more hours, or how many fewer hours, to reach 0℃?
Your Answer is
Correct Answer is C
Explanation
Looking at figure 3, we found that the temperature of bottom reached 0°C in about 23 hours;
Then found that the temperature of top had reached 0°C in about 8 hours, so the bottom probably Slow 23-8=15 hours