Brian Clegg - Lightning Often Strikes Twice: The 50 Biggest Misconceptions in Science

Also by Brian Clegg and published by Michael OMara Books

10 Short Lessons in Time Travel (Pocket Einstein Series)

First published in Great Britain in 2022
by Michael OMara Books Limited
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Tremadoc Road
London SW4 7NQ

Copyright Michael OMara Books 2022

All rights reserved. You may not copy, store, distribute, transmit, reproduce or otherwise make available this publication (or any part of it) in any form, or by any means (electronic, digital, optical, mechanical, photocopying, recording or otherwise), without the prior written permission of the publisher. Any person who does any unauthorized act in relation to this publication may be liable to criminal prosecution and civil claims for damages.

A CIP catalogue record for this book is available from the British Library.

ISBN: 978-1-78929-425-5 in hardback print format
ISBN: 978-1-78929-426-2 in ebook format

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CONTENTS

For millennia, folklore and proverbial wisdom have been used in an attempt to explain the world around us. Some of these beliefs, derived from experience, have later proved to have a basis in science for example, red sky at night really does suggest good weather next morning. Similarly, willow bark does indeed reduce pain, as it contains salicin, which in the form of salicylic acid is better known as aspirin.

Other explanations and beliefs are fictions, and have managed to linger through to the present despite plenty of scientific evidence to the contrary. And sometimes this proverbial wisdom has versions that are directly contradictory. Think, for example, of Many hands make light work and Too many cooks spoil the broth. Or it may have become a ritual that becomes detached from any sense of reality. A great example of this is Groundhog Day in America (the event, rather than the film). Taking place on 2 February every year, the legend has it that the actions of a groundhog (the best known being the semi-mythical Punxsutawney Phil) coming out of its burrow on that day predict what the weather will be like for the following six weeks. If it is overcast and the groundhog casts no shadow, then things are set fine. But if its sunny, the groundhog is supposed to be scared back into its burrow by the sight of its own shadow, bringing on six weeks of wintry weather.

In this book, we explore fifty commonly held beliefs about our world that are either misleading or downright false. Some are dependent on folklore take, for instance, the suggestion alluded to in the title of this book that lightning never strikes the same place twice, once so widely believed that it became a way to refer to an event that is unlikely to recur. Others, often featuring in more modern folklore, come from what feels like a more scientific source.

When first attempts at what we would now call science were being developed in ancient times, the standards for producing an explanation or theory were far less rigorous than is the case now. Ancient philosophers had a tendency to make scientific statements based primarily on argument, rather than on making a detailed examination of nature. The great ancient Greek philosopher Aristotle, for example, infamously asserted that women had fewer teeth than men. Simply counting teeth would have shown that this was a false premise but Aristotles authority as a philosopher (which held for many centuries) meant that many accepted the assertion as fact. As a result of long acceptance, while not all the ideas from the pre-scientific era were incorrect, we do get ancient errors recurring even today. With the slight proviso that taste and touch could be related, it was Aristotle who confidently asserted that there are five senses (sight, hearing, taste, smell and touch). We are still taught this at school despite it being long disproved.

Another possibility for misunderstanding comes in the form of modern myths that are spread by popular culture. Take, for example, the belief that eating sugary foods makes children hyperactive. This is strongly reflected in TV shows, from episodes of The Simpsons (where somehow European chocolate is considered far more intense in its impact) to Modern Family. It feels sensible that energy-giving sugar would make children get overexcited and it is often presented as if it were a scientific fact. Yet studies have been undertaken that conclusively show this is not the case. Once a pseudoscientific belief becomes part of the culture, however, it can be difficult to shake.

Often, such incorrect beliefs do no real harm, other than spreading misinformation. As it happens, sugar isnt great for children, so even though the reasoning for keeping sugar consumption down to avoid hyperactive behaviour isnt valid, the belief does no damage. In other cases, though, such beliefs can prove distinctly dangerous. The fifty examples here are not in this category. The aim is to entertain and inform. But there have been dangerous beliefs: from the early idea that smoking tobacco was good for you to more recent suggestions that MMR vaccinations cause autism, which had a devastating impact on the lives of some of those who believed them in the case of the MMR vaccinations, facilitating the spread of measles among children who werent inoculated, a disease that can cause brain damage and death.

Lightning Often Strikes Twice, by contrast, presents us with misleading concepts where the reality provides surprise and delight. Each topic offers a fascinating opportunity to find out more about science and to challenge what has been assumed to be true. The aim of this book is to bring the stories behind these misunderstandings and myths to life with a clear picture of the realities that lie behind them.

Lightning is a terrifying force of nature. There was a time when these dramatic flashes and bangs in the sky (thunder is just the sound made by lightning as it rips through the air, not a separate phenomenon) were considered to be the action of gods. But although we now know that lightning is caused by a build-up of electrical charge in clouds, probably due to ice particles bashing into each other, rubbing charged electrons away from atoms, it certainly is a phenomenal source of energy.

A typical lightning flash carries a similar amount of energy to the output of a mid-sized power station over the period of a second but that energy is emitted far quicker. As the electrical energy is discharged it sends air molecules flying at such speeds that localized air temperatures can reach between 20,000 and 30,000 C (36,000 and 54,000 F) over four times the temperature of the surface of the sun. Its this blast, ripping through the air molecules, that forms the distinctive rumble and crash of thunder.

Although in any particular location we might not see thunderstorms too often, they are not at all uncommon. As you read this, there are probably around two thousand on the go around the world, with an average of 8 million lightning strikes taking place each day. (There tend to be more in summer but its always summer somewhere.) Most bolts of lightning travel from cloud to cloud and never reach the ground, but its the strikes that link the clouds to the Earth that give lightning its fearsome reputation and most devastating outcomes blasting trees, starting fires and killing humans and animals.