The Project Gutenberg EBook of General Science, by Bertha M. ClarkThis eBook is for the use of anyone anywhere at no cost and withalmost no restrictions whatsoever. You may copy it, give it away orre-use it under the terms of the Project Gutenberg License includedwith this eBook or online at www.gutenberg.netTitle: General ScienceAuthor: Bertha M. ClarkRelease Date: August 25, 2005 [EBook #16593]Language: EnglishCharacter set encoding: ISO-8859-1*** START OF THIS PROJECT GUTENBERG EBOOK GENERAL SCIENCE ***Produced by John Hagerson, Kevin Handy, Sankar Viswanathanand the Online Distributed Proofreading Team athttp://www.pgdp.net GENERAL SCIENCE BY BERTHA M. CLARK, PH.D. HEAD OF THE SCIENCE DEPARTMENT WILLIAM PENN HIGH SCHOOL FOR GIRLS, PHILADELPHIA NEW YORK - CINCINNATI - CHICAGO AMERICAN BOOK COMPANY 1912PREFACEThis book is not intended to prepare for college entranceexaminations; it will not, in fact, prepare for any of the present-daystock examinations in physics, chemistry, or hygiene, but it shouldprepare the thoughtful reader to meet wisely and actively some oflife's important problems, and should enable him to pass muster on theprinciples and theories underlying scientific, and therefore economic,management, whether in the shop or in the home.We ...
The Project Gutenberg EBook of General Science, by Bertha M. Clark
This eBook is for the use of anyone anywhere at no cost and with
almost no restrictions whatsoever. You may copy it, give it away or
re-use it under the terms of the Project Gutenberg License included
with this eBook or online at www.gutenberg.net
Title: General Science
Author: Bertha M. Clark
Release Date: August 25, 2005 [EBook #16593]
Language: English
Character set encoding: ISO-8859-1
*** START OF THIS PROJECT GUTENBERG EBOOK GENERAL SCIENCE ***
Produced by John Hagerson, Kevin Handy, Sankar Viswanathan
and the Online Distributed Proofreading Team at
http://www.pgdp.net
GENERAL SCIENCE
BY
BERTHA M. CLARK, PH.D.
HEAD OF THE SCIENCE DEPARTMENT
WILLIAM PENN HIGH SCHOOL FOR GIRLS, PHILADELPHIA
NEW YORK - CINCINNATI - CHICAGO
AMERICAN BOOK COMPANY
1912PREFACE
This book is not intended to prepare for college entrance
examinations; it will not, in fact, prepare for any of the present-day
stock examinations in physics, chemistry, or hygiene, but it should
prepare the thoughtful reader to meet wisely and actively some of
life's important problems, and should enable him to pass muster on the
principles and theories underlying scientific, and therefore economic,
management, whether in the shop or in the home.
We hear a great deal about the conservation of our natural resources,
such as forests and waterways; it is hoped that this book will show
the vital importance of the conservation of human strength and health,
and the irreparable loss to society of energy uselessly dissipated,
either in idle worry or in aimless activity. Most of us would reproach
ourselves for lack of shrewdness if we spent for any article more than
it was worth, yet few of us consider that we daily expend on domestic
and business tasks an amount of energy far in excess of that actually
required. The farmer who flails his grain instead of threshing it
wastes time and energy; the housewife who washes with her hands alone
and does not aid herself by the use of washing machine and proper
bleaching agents dissipates energy sadly needed for other duties.
The Chapter on machines is intended not only as a stimulus to the
invention of further labor-saving devices, but also as an eye opener
to those who, in the future struggle for existence, must perforce go
to the wall unless they understand how to make use of contrivances
whereby man's limited physical strength is made effective for larger
tasks.
The Chapter on musical instruments is more detailed than seems
warranted at first sight; but interest in orchestral instruments is
real and general, and there is a persistent desire for intelligent
information relative to musical instruments. The child of the laborer
as well as the child of the merchant finds it possible to attend some
of the weekly orchestral concerts, with their tiers of cheap seats,
and nothing adds more to the enjoyment and instruction of such hours
than an intimate acquaintance with the leading instruments. Unless
this is given in the public schools, a large percentage of mankind is
deprived of it, and it is for this reason that so large a share of the
treatment of sound has been devoted to musical instruments.
The treatment of electricity is more theoretical than that used in
preceding Chapters, but the subject does not lend itself readily to
popular presentation; and, moreover, it is assumed that the
information and training acquired in the previous work will give the
pupil power to understand the more advanced thought and method.
The real value of a book depends not so much upon the information
given as upon the permanent interest stimulated and the initiative
aroused. The youthful mind, and indeed the average adult mind as
well, is singularly non-logical and incapable of continued
concentration, and loses interest under too consecutive thought and
sustained style. For this reason the author has sacrificed at times
detail to general effect, logical development to present-day interest
and facts, and has made use of a popular, light style of writing as
well as of the more formal and logical style common to books of
science.
No claim is made to originality in subject matter. The actual facts,
theories, and principles used are such as have been presented in
previous textbooks of science, but the manner and sequence ofpresentation are new and, so far as I know, untried elsewhere. These
are such as in my experience have aroused the greatest interest and
initiative, and such as have at the same time given the maximum
benefit from the informational standpoint. In no case, however, is
mental training sacrificed to information; but mental development is
sought through the student's willing and interested participation in
the actual daily happenings of the home and the shop and the field,
rather than through formal recitations and laboratory experiments.
Practical laboratory work in connection with the study of this book is
provided for in my _Laboratory Manual in General Science_, which
contains directions for a series of experiments designed to make the
pupil familiar with the facts and theories discussed in the textbook.
I have sought and have gained help from many of the standard
textbooks, new and old. The following firms have kindly placed cuts
at my disposal, and have thus materially aided in the preparation of
the illustrations: American Radiator Company; Commercial Museum,
Philadelphia; General Electric Company; Hershey Chocolate Company;
_Scientific American_; The Goulds Manufacturing Company; Victor
Talking Machine Company. Acknowledgment is also due to Professor Alvin
Davison for figures 19, 23, 29, 142, and 161.
Mr. W.D. Lewis, Principal of the William Penn High School, has read
the manuscript and has given me the benefit of his experience and
interest. Miss. Helen Hill, librarian of the same school, has been of
invaluable service as regards suggestions and proof reading. Miss.
Droege, of the Baldwin School, Bryn Mawr, has also been of very great
service. Practically all of my assistants have given of their time and
skill to the preparation of the work, but the list is too long for
individual mention.
BERTHA M. CLARK.
WILLIAM PENN HIGH SCHOOL.
CONTENTS
CHAPTER
I. HEAT
II. TEMPERATURE AND HEAT
III. OTHER FACTS ABOUT HEAT
IV. BURNING OR OXIDATION
V. FOOD
VI. WATER
VII. AIR
VIII. GENERAL PROPERTIES OF GASES
IX. INVISIBLE OBJECTS
X. LIGHT XI. REFRACTION
XII. PHOTOGRAPHY
XIII. COLOR
XIV. HEAT AND LIGHT AS COMPANIONS
XV. ARTIFICIAL LIGHTING
XVI. MAN'S WAY OF HELPING HIMSELF
XVII. THE POWER BEHIND THE ENGINE
XVIII. PUMPS AND THEIR VALUE TO MAN
XIX. THE WATER PROBLEM OF A LARGE CITY
XX. MAN'S CONQUEST OF SUBSTANCES
XXI. FERMENTATION
XXII. BLEACHING
XXIII. DYEING
XXIV. CHEMICALS AS DISINFECTANTS AND PRESERVATIVES
XXV. DRUGS AND PATENT MEDICINES
XXVI. NITROGEN AND ITS RELATION TO PLANTS
XXVII. SOUND
XXVIII. MUSICAL INSTRUMENTS
XXIX. SPEAKING AND HEARING
XXX. ELECTRICITY
XXXI. SOME USES OF ELECTRICITY
XXXII. MODERN ELECTRICAL INVENTIONS
XXXIII. MAGNETS AND CURRENTS
XXXIV. HOW ELECTRICITY MAY BE MEASURED
XXXV. HOW ELECTRICITY IS OBTAINED ON A LARGE SCALE
INDEX
GENERAL SCIENCE
CHAPTER I
HEATI. Value of Fire. Every day, uncontrolled fire wipes out human
lives and destroys vast amounts of property; every day, fire,
controlled and regulated in stove and furnace, cooks our food and
warms our houses. Fire melts ore and allows of the forging of iron, as
in the blacksmith's shop, and of the fashioning of innumerable objects
serviceable to man. Heated boilers change water into the steam which
drives our engines on land and sea. Heat causes rain and wind, fog and
cloud; heat enables vegetation to grow and thus indirectly provides
our food. Whether heat comes directly from the sun or from artificial
sources such as coal, wood, oil, or electricity, it is vitally
connected with our daily life, and for this reason the facts and
theories relative to it are among the most important that can be
studied. Heat, if properly regulated and controlled, would never be
injurious to man; hence in the following paragraphs heat will be
considered merely in its helpful capacity.
2. General Effect of Heat. _Expansion and Contraction_. One of the
best-known effects of heat is the change which it causes in the size
of a substance. Every housewife knows that if a kettle is filled with
cold water to begin with, there will be an overflow as soon as the
water becomes heated. Heat causes not only water, but all other
liquids, to occupy more space, or to expand, and in some cases the
expansion, or increase in size, is surprisingly large. For example, if
100 pints of ice water is heated in a kettle, the 100 pints will
steadily expand until, at the boiling point, it will occupy as much
space as 104 pints of ice water.
The expansion of water can be easily shown by heating a flask (Fig. I)
filled with water and closed by a cork through which a narrow tube
passes. As the water is heated, it expands and forces its way up the
narrow tube. If the heat is removed, the liquid cools, contracts, and
slowly falls in the tube, resuming in time its original size or
volume. A similar observation can be made with alcohol, mercury, or
any other convenient liquid.
[Illustration: FIG. 1.--As the water becomes warmer it expands and
rise in the narrow tube.]
Not only liquids are affected by heat and cold, but solids also are
subject to similar changes. A metal ball which when cool will just
slip through a ring (Fig. 2) will, when heated, be too large to slip
through the ring. Telegraph and telephone wires which in winter are