Things a Boy Should Know About Electricity Second Edition

=1. Some Simple Experiments.= Have you ever shuffled your feet along over the carpet on a winter's evening and then quickly touched your finger to the nose of an unsuspecting fr...

=24. Natural Magnets.= Hundreds of years ago it was discovered that a certain ore of iron, called lodestone, had the power of picking up small pieces of iron. It was used to ind...

=44. Early Experiments.= In 1786 Galvani, an Italian physician, made experiments to study the effect of static electricity upon the nervous excitability of animals, and especial...

=49. Single-Fluid and Two-Fluid Cells.= The simple cell (§ 45) is a single-fluid cell. The liquid is called the _electrolyte_, and this must act upon one of the plates; that is,...

=60. Electrical Connections.= In experimental work, as well as in the everyday work of the electrician, electrical connections must constantly be made. One wire must be joined t...

=65. Potential; Electromotive Force.= If water in a tall tank be allowed to squirt from two holes, one near the bottom, the other near the top, it is evident that the force of t...

=79. Electrolysis.= It has been seen that in the voltaic cell electricity is generated by chemical action. Sulphuric acid acts upon zinc and dissolves it in the cell, hydrogen i...

=81. Electricity and Chemical Action.= We have just seen, Chapter VII., that the electric current has the power to decompose certain compounds when they are in solution. By choo...

=84. Polarization.= It has been stated that a simple cell polarizes rapidly on account of hydrogen bubbles that form upon the copper plate. They tend to send a current in the op...

=88. Thermoelectricity= is the name given to electricity that is generated by heat. If a strip of iron, I, be connected between two strips of copper, C C, these being joined by...

=91. Electromagnetism= is the name given to magnetism that is developed by electricity. We have seen that if a magnetic needle be placed in the field of a magnet, its N pole wil...

=97. Forms of Electromagnets.= Fig. 95 shows a _straight, or bar electromagnet_. Fig. 96 shows a simple form of _horseshoe electromagnet_. As this form is not easily wound, the...

=99. Electromagnetic Induction.= We have seen that a magnet has the power to act through space and induce another piece of iron or steel to become a magnet. A charge of static e...

=103. The Coils.= We saw, § 102, that an induced current was generated when a current-carrying coil, Fig. 101, was thrust into another coil connected with a galvanometer. The ga...

=107. The Complete Telegraph Line= consists of several instruments, switches, etc., etc., but its essential parts are: The _Line_, or wire, which connects the different stations...

=115. Automatic Current Interrupters= are used on most common bells, as well as on induction coils, etc. (See § 104.) Fig. 115 shows a simple form of interrupter. The wire 1, fr...

=119. The Telephone= is an instrument for reproducing sounds at a distance, and electricity is the agent by which this is generally accomplished. The part spoken to is called th...

=126. The Dynamo=, _Dynamo-Electric Machine_ or _Generator_, is a machine for converting mechanical energy into an electric current, through electromagnetic induction. The dynam...

=133. Electric Current and Work.= The amount of work a current can do depends upon two factors; the strength (amperes), and the pressure, or E. M. F. (volts). A current of 10 am...

=138. Conductors and Insulators.= To carry the powerful current from the generating station to distant places where it is to give heat, power, or light, or even to carry the sma...

=145. Resistance and Heat.= We have seen that all wires and conductors offer resistance to the electric current. The smaller the wire the greater its resistance. Whenever resist...

=148. Incandescence.= We have just seen that the electric current produces heat when it flows through a conductor that offers considerable resistance to it. As soon as this was...

=152. The Electric Arc.= When a strong current passes from one carbon rod to another across an air-space, an _electric arc_ is produced. When the ends of two carbon rods touch,...

=154. Disruptive Discharges.= We have seen, in the study of induction coils, that a spark can jump several inches between the terminals of the secondary coil. The attraction bet...

=160. Currents and Motion.= We have seen, Chapter XII., that when coils of wire are rapidly moved across a strong magnetic field, a current of electricity is generated. We have...

=164. Electric Cars=, as well as boats, automobiles, etc., etc., are moved by the power that comes from electric motors, these receiving current from the dynamos placed at some...

=170. Central Stations=, as the word implies, are places where, for example, electricity is generated for the incandescent or arc lights used in a certain neighborhood; where te...

=171. The Many Uses= to which the electric current is put are almost numberless. New uses are being found for it every day. Some of the common applications are given below.