From Raindrops to Volcanoes: Adventures with Sea Surface Meteorology

DOVER BOOKS ON EARTH SCIENCES

DE RE METALLICA, Georgius Agricola. (60006-8)

PRECIOUS STONES, Max Bauer. (21910-0, 21911-9) Two-volume set

SEISMIC WAVES AND SOURCES, Ari Ben-Menahem and Sarva Jit Singh. (40461-7)

SNOW CRYSTALS, W. A. Bentley and W. J. Humphreys. (20287-9)

THE PIROTECHNIA, Vannoccio Biringuccio. (26134-4)

THE STORY OF MAPS, Lloyd A. Brown. (23873-3)

1001 QUESTIONS ANSWERED ABOUT THE WEATHER, Frank H. Forrester. (24218-8

FACTORS OF SOIL FORMATION: A SYSTEM OF QUANTITATIVE PEDOLOGY, Hans Jenny. (68128-9)

THEORY OF SATELLITE GEODESY: APPLICATIONS OF SATELLITES TO GEODESY, William M. Kaula. (41465-5)

EARTH, THE SAPPHIRE PLANET, Uri Lanham. (40677-6)

FLUVIAL PROCESSES IN GEOMORPHOLOGY, Luna B. Leopold, Gordon M. Wolman & John P. Miller. (68588-8)

THE NATURE OF LIGHT AND COLOUR IN THE OPEN AIR, M. Minnaert. (20196-1)

1001 QUESTIONS ANSWERED ABOUT THE MINERAL KINGDOM, Richard M. Pearl. (28711-4)

PRINCIPLES OF METEOROLOGICAL ANALYSIS, Walter J. Saucier. (65979-8)

1001 QUESTIONS ANSWERED ABOUT EARTHQUAKES, AVALANCHES, FLOODS AND OTHER NATURAL DISASTERS, Barbara Tufty. (23646-3)

1001 QUESTIONS ANSWERED ABOUT HURRICANES, TORNADOES AND OTHER NATURAL DISASTERS, Barbara Tufty. (25455-0)

ALL ABOUT LIGHTNING, Martin A. Uman. (25237-X)

THE LIGHTNING DISCHARGE, Martin A. Uman. (41463-9)

LIGHTNING, Martin A. Uman. (64575-4)

TABLES FOR MICROSCOPIC IDENTIFICATION OF ORE MINERALS, W. Uytenbogaardt and E. A. J. Burke. (64839-7)

THE ORIGIN OF CONTINENTS AND OCEANS, Alfred Wegener. (61708-4)

SCIENCE FROM YOUR AIRPLANE WINDOW, Elizabeth A. Wood. (23205-0)

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DUNCAN BLANCHARD’S life, like his book, has followed a trail with many crossing points—some quite unexpected. As a child he was determined to become an artist, but upon graduating from high school, in the midst of World War II, he enrolled in a course for apprentice toolmakers. After one rather unsuccessful year at toolmaking, he entered the Navy, was later commissioned an ensign and sent to Guam, where, he says, his interest in science began. One rainy night on his way to the Officers Club he found a soggy copy of a book called Men of Science in the jungle alongside his path. He dried it, read it, and for the first time began to understand what science was about. He decided to leave the Navy and pursue a scientific career.

Blanchard went back to school, received his B.S. from Tufts University, his M.S. in physics from Penn State University, and Ph.D. in meteorology from M.I.T. in 1961. He was at the Woods Hole Oceanographic Institution from 1951 to 1968, then at the Atmospheric Sciences Research Center at the University at Albany, New York, until his retirement in 1989. Blanchard was a frequent contributor to technical journals. Field trips for his work took him to Hawaii, the Caribbean, Costa Rica, and Iceland. Blanchard is a Fellow of both the American Meteorological Society and the American Association for the Advancement of Science.

Though From Raindrops to Volcanoes was Dr. Blanchard’s first book, in retirement he wrote and published The Snowflake Man, a biography of Wilson Bentley, the Vermont farmer who in 1885 took the world’s first photographs of snowflakes.

Copyright

Copyright © 1966, 1967 by Educational Services, Inc.

Copyright © Renewed 1994, 1995 by Duncan C. Blanchard

All rights reserved.

Bibliographical Note

This Dover edition, first published in 2004, is an unabridged republication of the 1967 Anchor Books edition of the work published by Doubleday & Company, Inc., Garden City, New York, as part of The Science Study Series. The author’s biography on page ii has been updated for this reprint.

Library of Congress Cataloging-in-Publication Data

Blanchard, Duncan C.

From raindrops to volcanoes : adventures with sea surface meteorology / Duncan C. Blanchard ; illustrations by Berton C. Heinrich, Jr.

p. cm.

Originally published: Garden City, N.Y. : Doubleday, 1967, in series: Science study series.

Includes index.

9780486150970

1. Meteorology. 2. Rain and rainfall. 3. Volcanoes. 4. Ocean-atmosphere interaction. I. Title.

QC863.B54 2004

551.5—dc22

2003067497

Manufactured in the United States of America

Dover Publications, Inc., 31 East 2nd Street, Mineola, N.Y. 11501

To

Duncan,

Becky,

and

Jonathan

who have just begun to explore

the wondrous world around them.

PREFACE

On the frontiers of science, from biology and medicine to geology, oceanography, and atmospheric science, significant discoveries are being made both by research teams and by the individual scientist. In this book I will introduce you to a small section of the frontier of the science of the atmosphere. In particular, I want to tell you about some experiments that have been done in an effort to understand what goes on in our vast ocean of air, especially when it interacts with the surface of the sea. The majority of the experiments can be carried out with a minimum of equipment. Some of the original experiments were more involved than the versions given here, but the results were the same. Many have revealed new facts about the workings of nature.

I hope that you will become sufficiently interested to try some of these experiments for yourself. Do not mind if others have done them before you. You still can have the excitement of that special moment when you realize that an experiment is demonstrating something you may have heard about but have never seen before. You need only one qualification—curiosity.

If you scan the chapter headings, you will note that they begin with raindrops and end with volcanic eruptions in the sea. How, you may ask, did I ever decide to discuss two subjects that appear to have no connection with each other? Was it a random selection of a few topics from many? The answer is simply that I have chosen to write in a chronological way about the subjects that I know best, the ones with which I have been associated. My research work began, about seventeen years ago, on raindrops. That work led to something else, and before I knew it I was working on subjects that on the surface appeared to have no obvious connection with raindrops. Yet there was a discernible trail that led from one subject to the other.

In taking you along parts of this trail I hope to convince you that this is the way all science operates. Each scientist follows a trail of his own choosing. Some will be more daring than others and will leave the main trail to push deep into the unknown. Some will be content to follow the trails of others, hoping to find along the way interesting things that have been overlooked by those who came first. Some will travel together, helping each other when the trail is difficult. But all have one thing in common; they are curious creatures who wish to understand the workings of nature.

As we follow the trail in this book, I hope you will become interested enough to strike out on your own. You will be surprised to find that you can begin your exploration in almost any spot that you wish. It can begin in your home, your backyard, on any pond or lake, or at the edge of the sea. It can begin any place, and once begun, you can follow it with enjoyment for a lifetime.

Table of Contents

DOVER BOOKS ON EARTH SCIENCES

Title Page

Copyright Page

Dedication

PREFACE

Chapter 1 - THE FLIGHT OF THE RAINDROPS

Chapter 2 - WHO SAYS A RAINDROP IS TEAR-SHAPED?

Chapter 3 - THE ORIGIN OF RAINDROPS

Chapter 4 - THE SURFACE OF THE SEA

Chapter 5 - EXPULSION FROM FLATLAND

Chapter 6 - DROPS IN THE AIR

Chapter 7 - SOMETHING ABOUT ELECTRICITY

Chapter 8 - ELECTRICITY FROM THE SEA

Chapter 9 - VOLCANOES, SEA WATER, AND ELECTRICITY

Chapter 10 - A VOLCANO AT THE SURFACE OF THE SEA

EPILOGUE

SUGGESTED READING

INDEX

A CATALOG OF SELECTED DOVER BOOKS IN ALL FIELDS OF INTEREST

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Chapter 1

THE FLIGHT OF THE RAINDROPS

Attend now, and I will explain how rain collects in the clouds above, and how the showers are precipitated and descend upon the earth. These words were written two thousand years ago by the Roman poet Lucretius. In his great poem, On the Nature of Things, he ranged over a vast number of subjects that included clouds, rain, thunder, and lightning. But, typical of the thinkers of his day, he never put his ideas to the test of experiment. Some were subsequently shown to have much merit. Others, however, were either so vague and general that they said nothing at all, or else they were little more than interesting and sometimes amusing speculations. For example, he said that one of the causes of rain was the wind pressing against swollen clouds. And the cause of lightning and thunder? Lucretius reasoned that when clouds collide they produce sparks and noise, as sometimes happens when two stones are struck together.

But it is not my intention to criticize the writings of Lucretius. It is all too easy to look backward down the long corridor of time and find error in anything. The ancients were struggling against a background of fear and superstition to find rational explanations for a multitude of natural phenomena. We should not criticize those who make an honest effort to understand the world around them. Rather, we should criticize those (they appear to be in the majority in every day and age) who unquestioningly will accept speculation and hypothesis before they have been put to the test of experiment.

The Beginning of Raindrop Studies

The ideas of Lucretius and his contemporaries on the formation of rain were carried down through the centuries and little attempt was made to improve upon them. Well over a thousand years went by, and nothing was added to our knowledge of how a raindrop is formed. It has been only within the past two hundred years that detailed daily or weekly measurements of rainfall, temperature, and atmospheric pressure have been made. By the end of the last century this collecting of data was being carried out with such zeal that the meteorological magazines devoted page after page to tables of this information. The rainfall was measured with great accuracy and reported to the nearest one-hundredth part of an inch.

In spite of the tremendous labors that went into the thousands of measurements of rainfall, no one seemed to ask the next questions: What are raindrops like? How big are they? Are they all the same size? Do they vary in size from rain to rain? Could I perhaps learn something of their origin if I determine their size and how they are distributed in rainfall? No one, I say, so far as we know, thought to ask these questions until, in the 1890s, a few men, one in this country and several abroad, began to wonder what raindrops were really like. I want to tell you about one of these men, about the ingenious and simple method he developed to measure the size of a raindrop, and what he found out about rain.

Wilson Bentley was a farmer who lived in the small town of Jericho, Vermont. But no ordinary farmer was he. Although he had no formal education beyond the public schooling available in Jericho and had his farming to attend to, he was somehow able to carry out a program of research on the mysteries of rain and snow. He is best known today for the thousands of beautiful photographs he made of snow crystals. But that is another story; we must stay with the raindrops.

In the year 1898 Bentley began his studies on rain, for he had the desire to add, if possible, a little to our knowledge regarding rainfall phenomena.... And add he did. For seven years, from 1898 through 1904, he made 344 measurements of the sizes of raindrops from seventy different storms.

How did he measure the raindrop size? Very simple; he let the rain fall for a few seconds into pans of fine uncompacted flour. If the flour was at least one inch deep, the raindrops did not splash, and each drop produced a dough pellet. He let the pellets dry and then measured the diameters. But what relationship was there between the size of the dough pellet and the original raindrop? Again Bentley showed his ingenuity, but we’ll let him speak for himself:

of an inch) produced pellets that were considerably flattened and had a longer diameter, exceeding by about one-third the diameter of the drop.

In 1904, Bentley published his findings in a scientific paper that is, in my opinion, among the very best ever written on the subject. He found that the largest raindrops are about one-quarter of an inch in diameter (about 6 mm). He suggested that in some cases the size was determined by the size of snowflakes within the cloud—the flakes had melted before they got to the ground. Bentley went on to tell how he had found different sizes of raindrops in different types of storms. He believed that there was a connection between lightning and raindrop size. And from an examination of his hundreds of raindrop samples he deduced that rain could have its origin either from melting snow or from a process that involved no ice or snow at all. But sometimes, he concluded, the sizes of the raindrops indicate that both processes may have operated at the same time.

Although Bentley’s paper was clear and well written, his strikingly original work and ideas went unnoticed. No one went out to check his measurements. No one gave much thought to the questions he had raised about the nature of rain. Nearly forty years passed before anyone in this country continued on with the work he had started. Finally, in 1943, J. O. Laws and D. A. Parsons, of the Soil Conservation Service, utilized Bentley’s flour technique and obtained more measurements of raindrop size. Since that time numerous scientists in many parts of the world have used the flour and other methods to discover much more about the sizes of raindrops.

Other Ways to Measure Raindrop Size

Before we turn to what has been revealed in raindrop studies, I want to tell you about two other methods that have been used to measure raindrop size. These methods, like Bentley’s, are extremely simple and can be mastered by anyone who has the curiosity and desire to learn something about rain.

In 1895, Professor J. Wiesner of Germany exposed sheets of absorbent paper to the rain. When the raindrops fell upon the paper they were absorbed, and the size of the spots could be related to the original size of the raindrops. This method is in common use today.

A popular paper is the ordinary filter paper that can be found in any chemistry laboratory; circular sheets of Whatman’s #1 paper of at least 15 cm¹ diameter have been a favorite of many scientists. If these papers are dusted lightly with a water-soluble dye, such as Methylene Blue powder (also common in the laboratory or the corner drugstore), the spots from the raindrops will be recorded permanently on the paper. And, I must warn you, they will be recorded on you unless you are extremely careful with the dye. Put the dye on the paper only out-of-doors or under a ventilating hood. You can treat the papers by putting them one at a time into a large Mason jar in which one or two teaspoons of the dye have been placed. With the cover on the jar rotate it to tumble the dye completely over one side of the paper. Remove the paper and eliminate any excess dye by snapping the back of the paper with the fingers. Afterward the treated side of the filter paper may not appear to have any dye attached to it, but believe me, it does. You will find out when you expose it to the rain.

A third method of raindrop size measurement utilizes screens. Some years ago I was looking for a way to sample the large raindrops that often fall from