Customer Reviews

Cats' Paws and Catapults: Mechanical Worlds of Nature and People

5 star:		(7)
4 star:		(3)
3 star:		(1)
2 star:		(1)
1 star:		(0)

 

 

What a pleasurable and stimulating book! Vogel is one of those rare authors who can communicate the essence of a complex technical field without either dumbing it down or making it so complex as to be unapproachable to the lay reader. "Cat's Paws and Catapults" is just full of elegant, clear text and beautiful pen-and-ink illustrations that make the difficult clear.

Vogel begins by comparing nature's solutions to problems of structure, propulsion and so forth with the creations of man, illustrating the differences and the similarities in how the two evolve. He differs with those philosophers who have argued that within nature might be found the ideal solutions to the problems of engineering and design, and gives convincing examples to support his case. He works though issues in structure, transport, proplsion and so on showing the differnt ways in which nature and man arrive at solutions, and argues why each may or may not be optimal.

One chapter is devoted to the question of scale, and how it influences design. For example, the houses built by humans are, despite all their nails and other fasteners, mainly held together by gravity. Things like nails and mortar serve mainly to keep bits from sliding off each other. That's not possible when building something the size of a bacterium; at that scale, gravity is essentially negligible.

Scale is similarly important in building a flying machine. Aircraft and insects fly in very different environments. Airplanes must fly fast to overcome gravity, whereas insects fly slowly, in an environment where drag is the main force to be overcome.

And that's just one small section. There are chapters on surfaces and angles, on soft versus hard, on pulling versus pushing, on the problem of making copies and many other topics as well.

As I read "Cat's Paws" I found myself making a tremendous number of penciled notes in the margin, arguing with some points and agreeing with others. It's not that there was that much I disagreed with, but rather that the book engaged me to the point that I felt I was in a dialogue with the author. It's that good.

If you're the kind of person who can't resist taking something apart to see what makes it work, buy this book. If you're fascinated by the workings of the natural world, buy this book. If you're just looking for a really good example of non-fiction writing in the best traditions of John McPhee, Tracy Kidder or Jeremy Bernstein, buy this book. You will not be disappointed.

Vogel's book attempts to refute the assertion that many the "techie" or the laymen make regarding the world's greatest innovations. Most will instantly assume that Mother Nature is the queen of all things brilliant when it comes to design, however this book has a different angle. Rather than touting Mother's praises, Vogel takes an analytic look at devices both natural and man-made and compares them. He discusses the truly divergent processes by which nature evolves and human engineering is refined, and points out a few cases where convergent solutions have emerged. A great book for any engineer who's also a fan of late night Discovery Channel.

This is a great book. Not great in the sense of changing the world as Newton, Darwin, and Freud did,
but great in the sense of well done. It is informative and entertaining at the same time.

Most of the book is a "compare and contrast" man made things and things in nature. A small part
is devoted to debunking the belief that whatever nature does is the best way to do it. Vogel
explains why airplanes do not have flapping wings. The laws of physics apply in both worlds.
Bones and I beams break under sufficient loads. The chapter titled "The Matter of Magnitude" is
important throughout the book. Things do not scale up. An elephant's legs are not as slender
as a deer's. Almost all of a small animal's mass is close to the surface, so it is easy to
disapate heat from a hard working muscle. A large animal would cook itself without additional
means of cooling.

There are chapters about shapes, surfaces, angles, rigidity, tension and compression, pulling
versus pushing, engines, transmissions, pumps, jets, manufacturing, and copying.

You do not have to be a mechanical engineer or have a great interest in biology to enjoy this book.
I think most readers with a variety of interests will enjoy it and learn a lot from it.
Even language fans will enjoy it. There is a pleasant phrase on almost every page, an expression
that will make you think "I wish I had said that."

"Cats' Paws and Catapults" is one of those rare books that are readable and enjoyable whether you have only a High School Education, or a Ph.D. in one of the sciences. It does a great job explaining important physical principles affecting our every day world that you never thought about. I learned quite a bit from reading this book and I recommend it to awide range of readers.

For anyone who has wondered about the design of nature and compared it to the design of man, where are the similitudes and the sticking differences.. why?.

This is a superb book that should make engineers have a deeper insight of the restrictions imposed by the enviroment, but also to see how nature's forms follow funtion

"This wonderful, insightful book will excite your curiosity and change the way you view the living world. Professor Steven Vogel, world authority on motion in fluids, takes the reader on a tour of discovery, comparing human inventions with the ingenuity of Nature. Beautifully and clearly written, this important new book brings biology and technology together for a wider readership. I really love this book and could not put it down." .... Christopher McGowan, paleontologist, author of "Dinosaurs, Spitfires, and Sea Dragons." ........ "Who is the better technologist, Mother Nature - source of seashells, spider webs, and birds' wings - or the human engineer - creator of skyscrapers, nylon, and airplanes. This engrossing question lies at the heart of a fine new book by Steven Vogel, an expert in biomechanics with a flair for genial philosophizing." ........ Samuel Florman, engineer, author of "The Existential Pleasures of Engineering."

Humanoid giants (4 m tall) would be incapable of moving, since doubling the length and width in a proportional manner increases volume and therefore weight by several times, so if such huge creatures exist, either they cannot resemble humans or they are not able to move. This is how the author addresses issues like shape, area and volume as well as their relation to weight. His amusing approach would have made physics a lot more fun at school. He also explains practical matters like "how many books can a standard shelf support without bending and what if you double the lenght..."

The author explains supporting structures like skeletons, towers, pillars, etc. and their stability if they rely on 1, 2, 3, 4 or more legs as well as their mobility (motion on ground, motion in water and flight).

Probably the main differece between nature design and human engineering is a matter of scale, since the majority of living beings are a lot smaller than humans (the scale is shown in an extremely interesting graph). The author mentions that the main difference when choosing a flying method between an airplane and a bird is size and therefore weight, since weight multiplies faster than area. This is why an airplane requires a lot more flight speed. This section is extremely interesting, I will probably read it again.

Other chapters deal with pumps, valves, motors, engines and propulsion systems. I must say that reading through this section was quite difficult, some notions in mechanics are probably helpful. In the end I could manage to understand them after a second reading of some paragraphs (at least the basic concepts or underlying principles, though not the mechanics of the engines itself). This was the only thing that made the book a bit less enjoyable to me.

Finally, the author explains the materials preferred by nature and by the human engineer, as well as their properties (metals as opposed to compound materials like wood, bone, cartilage, etc.). He explains flexibility, rigidity, strength, etc. he basically explains how all this materials react differently to tension, pressure, weight, heat, etc. Metals for example tend to create more heat by friction than natural materials, so cooling systems are an essential part of human made engines.

This book proved to be unexpectedly fascinating. It presented a wide-ranging comparison of human technology with the way nature gets things done. Several great questions were asked: e.g. why do humans use metals so much, but not nature?

Examples cover a huge range of nature. His coverage is authoritative, well-documented and balanced. It was very refreshing to read a nature book with such a different perspective.

A wonderful book. Steven Vogel has the skill to to grasp attention of the reader and to mantain it over the whole book. And he can explain the way many very complex mechanical items work or many phisical law in a very clear way and with great rigour.Really, a wonderful book everyone must read.

Highly readable, informative, and lively. Addresses questions about biology I have wondered about, such as why living things never have metal parts. I am grateful for its introducing me to many engineering concepts. The problem is that Vogel covers too many topics too superficially. For many of the topics, I found myself wishing for a fuller, more detailed, treatment.