Riddles in Your Teacup

P Ghose, Partha Ghose, D Home

• Publisher: CRC Press
• Year: 2020
• eBook ISBN: 9781000153903
• Topic: Philosophy
• Subtopic: Philosophical Metaphysics

Natural phenomena and ordinary, everyday things often contain surprises and puzzles when we attempt to understand them in terms of basic physical principles. Trying to explain what we see around us can even help us to understand physical principles more fully. Written by two well-known popularizers of science, Riddles in Your Teacup, Second Edition focuses on many puzzles, both simple and advanced, that relate to these phenomena. Revised and enlarged, this fascinating second edition contains challenging questions about everyday scientific mysteries. It presents an amusing and entertaining collection of puzzles and solutions, including some riddles that have continued to defy explanation.

Questions

1

Kettle Croon Physics around the Kitchen

“All our knowledge brings us nearer to our ignorance.”

T S ELIOT

“It isn’t that they can’t see the solution. It is that they can’t see the problem.”

G K CHESTERTON

Kettle Croon

We are all familiar with the hissing sound (called the “singing” of the kettle) that starts a few moments after the kettle is put on the fire to boil water. This sound gradually increases and then suddenly drops when the water starts to boil. In fact, we know from the sudden drop of the sound that the water is ready, boiling. Have you ever wondered what causes the kettle to “sing”?

Spoon in a Teacup

One often puts a metal spoon into the china cup before pouring hot tea into it. Why? Which is safer to use, a thin-walled cup or a thick-walled one?

Einstein in your Teacup

Erwin Schrödinger was an eminent physicist who discovered the fundamental equation of quantum mechanics which describes the behaviour of atomic and sub-atomic entities. Schrödinger’s wife remembered Einstein every time she poured her tea. This is because it was Einstein who first explained to her and to her husband why wet tea leaves (which are heavier than the liquid) always collect at the centre of the bottom of a cup when the tea is rotated by a spoon for a while and then allowed to settle. This is what Schrödinger wrote to Einstein on 23 April 1926 (reprinted in Letters on Wave Mechanics, edited by K Przibram, Philosophical Library, p 27): “It just happens that my wife had asked me about the ‘teacup phenomenon’ a few days earlier, but I did not know a rational explanation. She says that she will never stir her tea again without thinking of you.”

Erwin Schrödinger (1887–1961) was born and educated in Vienna, Austria. Until the age of 11 he was taught at home, and his father encouraged his interest in nature with a microscope and other equipment. In 1926 he discovered the central equation of quantum mechanics for which he shared the 1933 Nobel Prize for physics with Paul Dirac. Photograph courtesy of AIP Neils Bohr Library.

Next time you have tea, turn it with your spoon and notice where the leaves settle. Why do you think the leaves settle at the centre and not get pushed to the walls by the centrifugal effect?

Paul Dirac (1902–1984) was born and educated in Bristol, England, before going to Cambridge University to do research. He shared the 1933 Nobel Prize for physics with Schrödinger for the development of quantum mechanics. Dirac was an extremely original thinker but notoriously reticent. This may explain why he is still relatively unknown to the general public. Dirac’s friend Peter Kapitza, the Russian physicist, once gave him an English translation of Dostoevski’s classic Crime and Punishment. Later when Kapitza asked him how did he like the book Dirac replied in his characteristically succinct way: “It is nice, but in one of the chapters the author made a mistake. He describes the Sun as rising twice on the same day”. Some of the readers of this present book may wish to try to find out in which chapter this occurred. Photograph courtesy of AIP Neils Bohr Library.

A Hole in a Tea Pot

Why is a small hole usually made on the lid of a tea pot?

The Teetotaller’s Dilemma

Some like to pour milk first and then tea, others prefer to add milk to the tea. Is there any difference between the two?

Fire without Hazard

Why doesn’t the whole gas cylinder catch fire when the burner is ignited?

The inner Core

When one makes ice cubes in a refrigerator, one usually finds that the outer part of the cubes is transparent whereas the inner core is opaque. Why?

An Apple a Day

Why does the cut surface of an apple turn brownish after some time?

Ovens with a Difference

Microwave ovens are now quite common in kitchens. Do you know how they work?

Don’t Lick an Ice Tray

Have you ever tried to hold a really cold frosted ice tray? If you have, you must have noticed that your fingers tend to stick to the tray. Why? Don’t ever try to lick the tray—it will be a very painful experience!

From Fermi to the Frying Pan

The famous Italian physicist Enrico Fermi once asked a student during an examination: “The boiling point of olive oil is higher than the melting point of tin. Explain how it is then possible to fry food in olive oil in a pan”. (Italian saucepans are wholly made of tinned copper.) What is the answer?

Coiling Chocolate

The coiling of thick molten chocolate as it is poured onto a plate or a slab of ice-cream must have struck you as odd. What on earth makes it coil?

Leaping Liquid

The nuisance caused by milk spilling over when boiled is well known. One has to keep a constant watch and stir the milk to prevent it spilling. Why does milk have this peculiar property?

Sou...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Dedication
• Table of Contents
• Foreword
• Preface to the Second Edition
• Acknowledgments and Bibliography
• Questions
• Answers
• Index