Exercises in Practical Physics for Schools of Science Volume 1 (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1899 Excerpt: .... and compression of Fig. 88---To show the relation between the pressure, and volume of a gas. Support the open tube with its open end upwards, and at such a height that the mercury stands at the same level in the closed and open tubes. The imprisoned air is then at the same pressure as the air outside. If the closed tube is uniform in bore, and the inside of the sealed end is nearly flat, the volume of the imprisoned air is proportional to the length of tube occupied by the air, so that if the air is made to occupy one-half the original length of tube its volume is one-half the original volume. The pressure upon the enclosed air is equal to the pressure due to the column of mercury between the level of mercury in the closed tube and that in the open tube, plus the pressure of the atmosphere. Observe the height of the barometer, and make the difference of level of the mercury in the two tubes equal to it by lifting the open tube. Then record in your note-book as follows: Height of the barometer, ----cm. Length of air column when the mercury is at the same level in both tubes, that is, when the imprisoned air is at atmospheric pressure, cm. Height of barometer cm. + equal height in tube, cm. Length of air column under pressure of two atmospheres, cm. The pressure to which the enclosed air is subjected in the second case is double that of the first case; find the proportion in which the volume of air, represented by the length of air column, has been diminished. b) Lower the open tube until the air in the closed tube almost reaches the india-rubber junction.. Measure the length of the air column, and the difference of level of the mercury in the two tubes. Repeat the experiment by reading the volume of air and the head of mercury at every few centimetr...