Question 14 Answer and Explanation _ACT April 2013 Form 71G Science Section

14. Two streams, Stream A and Stream B, are identical in all respects, except that water flows rapidly in Stream A but is nearly at rest in Stream B. Based on the results of the experiment, during a prolonged period of -5℃ weather, water at the top of which stream is less likely to begin freezing first, and why?

F. Stream A, because Figures 2 and 3 indicate that turbulent water freezes more slowly than does water at rest.

G. Stream A, because Figures 2 and 3 indicate that turbulent water freezes more quickly than does water at rest.

H. Stream B, because Figures 2 and 3 indicate that turbulent water freezes more slowly than does water at rest.

J. Stream B, because Figures 2 and 3 indicate that turbulent water freezes more quickly than does water at rest.

Answer and Explanation

Your Answer is

Correct Answer is F

Explanation

Look at figure 1 first, and know that the difference between Tank X and Tank Y is that the water in Tank X is flowing, while the water in Tank Y is net.

So Stream A is equivalent to Tank X, and Stream B is equivalent to Tank Y;

Looking at figure 3, it is found that the temperature of the top in Tank Y reaches 0°C in about 8 hours , and figure 2 shows that the temperature of the top in Tank X reaches 0°C in about 12 hours, so it can be concluded that the faster the flow rate of water, the slower it freezes;

In the same way, Stream A with a fast flow rate will freeze more slowly