The Francis W. Parker School Year Book (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. 1918 Excerpt: ...way. Experiment.--The electro-magnet. Place a compass in a coil of wire and pass an electric current through the coil. Let the children see that an iron magnet is not necessary to set up a magnetic disturbance. Discuss the uses of electro-magnets. As an outcome of the study of the electro-magnet, one of the "Some groups will ask how a magnet can be made from a piece of iron. In answer to this question the theory of magnetism may be very simply stated. boys devised an electro-magnet crane and another planned an electric reciprocating engine. AN ELECTRO-MAGNET CRANE The electro-magnet crane is a new invention for lifting steel and iron without fastening. The principle on which this works is an electric current circling in an insulated wire, which is wrapped around a piece of soft iron. Some men think a piece of iron or steel is made of little particles, which have two poles, a north and a south pole. These little particles cannot be seen even under a very powerful microscope. These poles, before the circling of electricity, are all facing in different directions, but while the electricity passes around it, the north poles all face in one direction and create a power to draw steel or iron. The reason steel is not used for an electromagnet is because once steel becomes magnetized it stays magnetized for a long time, but iron loses all magnetism as soon as the current is broken. February 25, 1918. John. III. Steamship Lines.--This topic has no related laboratory work. IV. Influence of Ice on Steamship Routes.--Why do fogs occur about icebergs? In order to solve this problem, it is necessary for the children to know something about evaporation and condensation. Afterwards, application of these topics is made to the distribution of rainfall over the earth. Ex...