Smaller Class-Book of Modern Science. By the authors of “Class-Book of Modern Science,” etcJohn Heywood, 1869 - 160 pages |
Other editions - View all
Common terms and phrases
adhesion atmosphere atoms axle ball balloon becomes body falls boiling carbonic acid cause centre of gravity centrifugal force clouds cohesion cold colours condensation cools density depth distance earth earth's surface elastic equal ether evaporation expand falling body feet a second fixed pulley fogs force of gravity freezing friction fulcrum glass greater ground heat horse human voice images inches inclined plane increases intensity latent heat length less Lesson 43 lift lifting force light liquid machine MAGDEBURG HEMISPHERES mass metal miles motion movable pulley move number of vibrations particles pass pendulum pressure produced pulley quicksilver radiation raise Ramsgate rapid rapidly rarefied rays reflected refraction retina rise saturated screw side solar solid sound-waves space specific gravity square steam stone string sun's temperature THAUMATROPE thrown tube vapour velocity of sound vessel Vitreous Humour warm wedge weight wheel wheel-and-axle wind wood
Popular passages
Page 103 - ... it is a common thing to see a flash of light, even in broad day, when the ball strikes the target. And if I examine my lead weight after it has fallen from a height, I also find it heated. Now here experiment and reasoning lead us to the remarkable law that the amount of heat generated, like the mechanical effect, is proportional to the product of the mass into the square of the velocity. Double your mass, other things being equal, and you double your amount of heat; double your velocity, other...
Page 78 - An increase in the temperature of the air equal to i c causes a corresponding increase of ri4 feet per second in the velocity of sound: here the density being diminished, the elasticity remains the same. The velocity is directly proportional to the square root of the elasticity of the air, and inversely as the square root of the density. Sound, in fact, travels through different media with very different degrees of velocity; thus, starting with air as unity or one, the following velocities have been...
Page 54 - The combined centre of gravity of machine and foundation should be, to the extent possible, in the same vertical line as the centre of gravity of the base line.
Page 38 - In this class, the fulcrum is at one end, the weight at the other, and the power between them. In the various movements of the body, we have instances of all three kinds of levers. The skull, as it nods backwards and forwards upon the atlas, is an instance of the first class of levers.
Page 79 - The wave-length is found by dividing the velocity of sound per second by the number of vibrations executed by the sounding body in a second. Thus a tuning-fork -which vibrates 256 times in a second produces in air of 15° C., where the velocity is 1,120 feet a second, waves 4 feet 4 inches long.
Page 122 - If the steam were predominant, the bubble would burst from within outwards ; if the air were predominant, the bubble would be crushed inwards. Here, then, we have the true definition of the boiling point of a liquid. It is that temperature at which the tension of its vapour exactly balances the pressure of the atmosphere.
Page 41 - The teeth on the axle are termed leaves. The mode of calculating the power gained is to divide the number of teeth in the wheel by the number of leaves in the pinion ; thus if the latter has 12 and the former 144, then 144 + 12 = 12, the power gained ; which may be either velocity or intensity be- • tween weights or forces.
Page 154 - POLE. a. As the earth turns on its axis from west to east...
Page 84 - ... a note a fifth above the octave of the whole string. In general terms, the number of vibrations is inversely proportional to the length of the string. 2. The...
Page 26 - It is explained in a preceding paragraph, that a body falls four times as far in two seconds as in one, although the velocity at the end of two seconds is only doubled. For the same reason, a body shot upwards with double velocity, rises four times as far...