Two engineering students wanted to determine the humidity in their dorm room. They decided to fill several glasses with tap water and add a little ice to the first glass, a little more to the second glass, and the most to the last of six glasses, as shown in Fig. 11.30. The temperature of the water in each glass, after some time had passed, was measured with a simple thermometer, which read 22 8C in the room and 19 8C, 17 8C, 15 8C, 12.5 8C, 10 8C, and 7 8C in the respective glasses. They noticed that moisture was collecting on the outside of each of the last four glasses. Approximate the humidity.