Physics

=352. A Comparison of Sound and Light.=--Light from the standpoint of physics is considered much as is _sound_, as a _mode_ of _motion_; one affecting the ear, the other produci...

=71. Force.=--We have been studying various forces, such as air pressure, pressure in liquids, and the force of elasticity in solids, and have considered them simply as pushes o...

_104. Work._--"Whenever a force moves a body upon which it acts, it is said to do work upon that body." For example, if a man pushes a wheelbarrow along a path, he is doing work...

=317. What is a Sound?=--This question has two answers, which may be illustrated as follows: Suppose that an alarm clock is set so that it will strike in one week and that it is...

The developments in wireless communication have been so rapid during recent years that a more extended account, than that given in Art. 417 of the apparatus and methods used at...

=177. Specific Heat.=--In the study of density and specific gravity it is made clear that different substances differ widely in the amount of matter contained in equal volumes,...

=255. The Magnetic Effect.=--Of all the effects of electric currents, it is generally conceded that the _magnetic effect_ is the one of _greatest practical importance_, and it i...

=151. Conduction.=--To illustrate conduction, place in a gas flame the ends of same metal wires supported as in Fig. 130. In a short time the other ends of the wires become hot...

=14. Size of Molecules.=--The difference between solids, liquids, and gases has been explained as due to the different behavior of molecules in the three states of matter. That...

=296. Current Induced by a Magnet.=--The discovery in 1819 that a current in a conductor can deflect a magnetic needle or that it has a magnetic effect, led to many attempts _to...

The amount of this force may be computed as follows: First, the card stays on the end of the tube until the _weight_ of water from above equals the force of the water from below...

=213. Electrical Charges.=--The ideas gained in the study of magnetism are of assistance in the study of electricity in giving some fundamental ideas and principles that will of...

=51. Weight of Air.=--It is said that savages are unaware of the presence of _air_. They feel the _wind_ and hear and see it moving the leaves and branches of the trees, but of...

=280. Electroplating.=--If two carbon rods (electric light carbons answer very well) are placed in a solution of _copper sulphate_ (Fig. 260) and then connected by wires to the...

=199. Magnets.=--Since the times of the early Greek philosophers men have known of certain stones that have the property of attracting to themselves objects of iron and steel. S...

=237. Sources of Electric Currents.=--In studying the production and distribution of static electricity it was seen that if two bodies at _different potentials_ are connected by...

=1. Physics, an Explanation of Common Things.=--Many students take up the study of physics expecting to see wonderful experiments with the "X" rays, wireless telegraphy, dynamos...

=138. Importance of the Study of Heat.=--Heat is brought to our attention through the sensations of heat and cold. In winter, we warm our houses and prevent the escape of heat f...

=415. Oscillatory Nature of the Spark from a Leyden Jar.=--In studying sound (Art. 339), the sympathetic vibration of two tuning forks having the same rate of vibration was give...

e. Metallic thermometers depend upon the movement due to the expansion of a coiled strip of metal which turns a pointer on the dial of the instrument. (See Fig. 129.)

=35. Pressure of Liquids against Surfaces.=--The sight of a great ship, perhaps built of iron and floating on water, causes one to wonder at the force that supports it. This sam...

(1) Rectilinear Propagation of Light 388 (2) Photometry and Law of Reflection 393 (3) Mirrors and Formation of Images 400 (4) Refraction of Light 410 (5) The Formation of Images...

(1) Sources and Effects of Heat 159 (2) Temperature and Expansion 162 (3) Expansion of Gases, Liquids and Solids 167 (4) Modes of Transmitting Heat 173 (5) Convection, Heating a...

(1) Work and Energy 119 (2) Power and Energy 123 (3) The Lever and Simple Machines 129 (4) Wheel and Axle and Pulley 136 (5) Efficiency and the Inclined Plane 142 (6) Friction a...

(1) Sound, Source, Speed, Media 354 (2) Waves and Wave Motion 357 (3) Intensity and Pitch of Sound 363 (4) Musical Scales and Resonance 368 (5) Interference, Beats, Vibration of...

(1) Force, how Measured and Represented 79 (2) Motion. Newton's Laws 85 (3) Resolution of Forces 96 (4) Moment of Force and Parallel Forces 99 (5) Gravitation and Gravity 103 (6...

(1) Electrification and Electrical Charges 243 (2) Electric Fields and Electrostatic Induction 247 (3) Electric Theories, Distribution and Electric Charges 252 (4) Potential, Ca...

(1) Molecular Motions in Gases 13 (2) Molecular Motions in Liquids 18 (3) Molecular Forces in Liquids 21 (4) Molecular Forces in Liquids and Solids 27 (5) Molecular Forces in So...