A Guide to the Scientific Knowledge of Things Familiar (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. 1875 Excerpt: ... greatly assists the cooling process. Q. Why are hot tea and soups Cooled the faster for being stirred about? A. 1st--Because agitation assists in bringing the hottest particles to the surface: 2ndly--The action of stirring agitates the air, and brings it more quickly to the soup or tea: and PUMPS AND SYPHONS. )it)5 3rdly--As the hotter particles are more rapidly brought into contact with the air, convection is more rapid. Blowing tea or broth cools it also. (Seep. 186.) Q. If a shutter be closed in the day-time, the stream of light (piercing through the crevice) seems in Constant agitation. Whi is this? A. Because little motes and particles of dust (thrown into agitation by the convective currents of the air) are made visible by the strong beam of light, thrown into the room through the crevice of the shutter. Q. Why can we not See the air? A. Because it is perfectly transparent, i. e. permits all the rays of light to pass through it without reflecting any. Q. Why does water Bise in a common pump? A. Because the pressure of the air is removed from the water in the pipe of the pump by the action of the sucker; but not from the water in the well. Take a tube (shaped like a u) partially filled with water, and let an equal weight be fitted to each orifice: so long as the weights are undisturbed, the water will remain at the same level on both sides of the tube: but if one weight be removed, its place will be instantly occupied with an equal weight of water. So in a pump, the air may be compared to these two weights; as the action of tbe sucker removes one, water rushes into the pipe to counterbalance the weight of air pressing on the water in the well. i 2 Q. How high can atmospheric Pbesstjbe make water rise in a pipe of a pump? A. About 30 feet above the lev...