Driving Force: The Natural Magic of Magnets

by Livingston

Driving Force unfolds the long and colorful history of magnets: how they guided (or misguided) Columbus; mesmerized eighteenth-century Paris but failed to fool Benjamin Franklin; lifted AC power over its rival, DC, despite all the animals, one human among them, executed along the way; led Einstein to the theory of relativity; helped defeat Hitler's U-boats; inspired writers from Plato to Dave Barry. In a way that will delight and instruct even the nonmathematical among us, James Livingston shows us how scientists today are creating magnets and superconductors that can levitate high-speed trains, produce images of our internal organs, steer high-energy particles in giant accelerators, and--last but not least--heat our morning coffee.

From the "new" science of materials to everyday technology, Driving Force makes the workings of magnets a matter of practical wonder. The book will inform and entertain technical and nontechnical readers alike and will give them a clearer sense of the force behind so much of the working world.

Genres: Nonfiction, Physics, Science

336 pages, Paperback

First published April 1, 1996

Reviews

[Senni Oksanen · Rating 4 out of 5]

Olipas mitä ihastuttavin kirja! Joissakin kohdissa olisin kaivannut eksaktimpaa selitystä, ja jotkut teknologiset aiheet ovat ajan saatossa vanhentuneita - muuten kirja oli suorastaan mahtava. Varsinkin suprajohteet sekä magneettien käyttö lääketieteessä sekä teknologiassa olivat mitä mielenkiintoisimpia.

Myös magnetismin esiintyminen/syntyminen atomien elektronien spinien suhteesta aineiden magneettisten alkeisalueiden avulla avarsi mieltäni. Tajunnan räjäytti kirjan loppupuolella oleva selostus siitä, miten sähkö ja magnetismi on saman asian eri ilmentymiä - se, kumpaan kastiin ilmiö kuuluu riippuu suhteellisuudesta!!!

”Magneettikentät ja magneettiset voivat periaatteessa vain sähkövarauksen liikkeen suhteellisuusteoreettisia vaikutuksia.” Sama virta indusoituu riippumatta siitä, liikutetaanko johdinta vai magneettia.

[Unreliable Narrator · Rating 3 out of 5]

I only got half way through this + some skimming, which answered most of the questions I had and then some. The author writes in a fairly dorky style, but is also very clear. He keeps repeating/ reminding us of some basic magnet facts, which I found very helpful. I read this book to learn more about magnetic elements and the earth's magnetic core, but he really got me interested in the basics of electromagnetism, and alloys/ material science. Pairs well with Primo Levi's Periodic Table.

[Pauline · Rating 4 out of 5]

A lot of fascinating facts, science explanations I could mostly follow, and a survey of the surprisingly numerous and diverse uses of magnets in our lives today. I was curious about diamagnetism, which he mentioned briefly but did not discuss, so I'll have to look elsewhere for that, but I learned lots anyway.

[Mark Bates · Rating 3 out of 5]

Okay book about magnets and magnetic fields, got the impression the author was trying to show how much he knew and you didn't. Kind of wandered.

[Alexander Fontana · Rating 3 out of 5]

Magic:

1. the art of entertaining with illusions and sleight of hand
2. the supernatural
3. qualities and objects that are mysterious and awe-inspiring even though we know they are real and not supernatural  Magnets / Magnetic power

Magnes is the name of the Shepard who discovered magnetic powers when the nails in his shoe where attracted to a rock or
It was named after Magnesia which is a part of Greece where loadstones were found

Magnetic Rocks are called loadstones. In China they are called tzhu shih “loving stone” because they attract. French all it aimant which means both “magnet” and “loving affection.”

Magnets were probably discovered around 1200 B.C.

Permanent Magnets

Loadstones are made of magnetite (compound of iron (Fe) and oxygen (O) = Fe3O4
1920’s Cobalt-Chromium Steel magnets = 1 Megagauss (MGOe) = 4x stronger than carbon steels = 10x stronger than loadstones. Can conduct electricity.
1930’s Alnico magnets = type found on Scottie dogs and guitars = aluminum, nickel and cobalt + 50% iron = 8 MGOe. Can conduct electricity.
Ferrite magnet = weak gauss but cheap to make = most common magnet
Neodymium Rare Earth Magnet = N40+
Neodymium is used in the strongest permanent magnets known - Nd2Fe14B. These magnets are cheaper, lighter, and stronger than samarium-cobalt magnets. Neodymium magnets appear in high-quality products such as microphones, professional loudspeakers, in-ear headphones, Dokodemo Magnets, guitar and bass guitar pick-ups and computer hard disks where low mass, small volume, or strong magnetic fields are required.
Health Hazards
Neodymium magnets should always be handled carefully. Some that are slightly larger than the size of a penny are powerful enough to lift over 10 kilograms. Strong magnetic fields can disrupt the operation of some internal medical devices such as pacemakers. While most solid state electronic devices are not affected by magnetic fields, some medical devices are not manufactured to mitigate the effects of strong magnetic fields. These design flaws can be hazardous to patients using these devices.[1]. If swallowed, neodymium magnets can cause lethal conditions by joining up inside the intestine.[2]
An NIB's magnetic force increases with the size of the piece of ferromagnetic metal and larger neodymium magnets can severely pinch skin or fingers, or even break bones when suddenly attracted to a magnetic object. Operating a large neodymium magnet close to smaller magnetic objects (keys, pens, etc.) and larger magnetic surfaces (radiator or a car, for example) can be dangerous if the person is caught between the magnet and the magnetic object or surface.
Neodymium magnets are made with special powders and coatings, so they are very fragile. They are often plated with a metal such as nickel. The magnets can fracture at temperatures over 150 °C, or under impact as a result of their own acceleration. When this happens, in some cases the magnets may break apart so suddenly that flying pieces can cause injury.
[edit] Other dangers
Caution must be taken when using neodymium magnets. A neodymium magnet is powerful enough to destroy the contents of a floppy disk to such an extent that the information is unrecoverable, a guarantee not present with techniques such as formatting the disk. In regards to the information contained on the magnetic stripes of credit cards, neodymium magnets are amongst the only materials that can successfully erase this data. Neodymium magnets are often strong enough to not only magnetize color CRT shadow masks, but also physically deform the mask itself. Such damage is typically not repairable by degaussing.


Temporary Magnets

Electromagnets

Force

1. If free to rotate magnets point relatively to North and South Pole, North Poles point to N

2. Like poles repel, opposites attract

3. Magnetic forces attract only magnetic materials like iron and steel, not wood or glass

4. Can influence or attract from a distant and through some objects / certain thicknesses

5. While magnetized, temporary magnets act like permanent magnets.

6. A coil of wire with an electric current flowing through it becomes a magnet

7. Putting iron inside a current-carrying coil increases the strength of the electromagnet.

8. A changing magnetic field induces an electric current in a conductor

9. A charged particle experiences no magnetic force when moving parallel to a magnetic field, but when it is moving perpendicular to the field, it experiences a force perpendicular to both the field and the direction of motion.

10. A current-carrying wire in a perpendicular magnetic field experiences a force in a direction perpendicular to both the wire and the field.

Strength = saturation magnetization

Duration of permanence = amount of opposite force needed to neutralize = coercivity

Gauss = Named after physicist Carl Friedrich Gauss = 1 gauss = twice the magnetic pull of the earth. 1 Tesla = 10,000 guass.

[Tapani Aulu · Rating 3 out of 5]

Ostin jääkaappimagneetteja tämän lukemisen innoittamana. Just niin kutkuttavan innostava kuin magneettikirjan olettaakin olevan. Toki jo parikymmentä vuotta vanha, joten varsinkin hiukkaskiihdytinasiat jo vähän vanhentuneita.