Ever wondered whether an old-fashioned sand-filled egg-timer sitting on a kitchen scale would appear to be lighter while the sand was actually running? Or why golf balls have dimples? Scientific discovery, as these two books remind us in rather different ways, has always depended on being curious about things, often very simple things.
Both authors have given a great deal of thought not just to their subject matter, but rather to the manner in which an audience may best be persuaded that the subject really is worthy of their attention. Not because the audience might otherwise regard it as trivial, but rather the reverse. Louis Bloomfield has in mind an audience of arts majors, for whom science is clearly an awesomely difficult prospect, and his book is the product of several successful years' effort at teaching this level of American college student. Given that a reasonable reaction to the sand-filled egg-timer question might be "who cares?", the approach we see here is to engage the students' curiosity, and encourage them to think. "One of the goals of this book," he says, "is to remind students that science can be understood and that it need not be so scary. However, because science requires thought, students who are afraid to think will continue to fear itI" His book - from the title How Things Work onwards - is therefore full of questions, and the students are constantly encouraged to exercise their curiosity in seeking answers. Everyday life features strongly here, too. The notion that physics is all around you comes through, with a baseball, vacuum cleaner, bicycle, car engine, cd player, computers and many other devices and phenomena getting extended treatment. And almost, but not entirely, at a qualitative level. There is only the minimum of calculation and mathematics here - again, very much with the arts majors in mind. Occasionally the questions can seem rather trivial, and the everyday examples are always American - the baseball, the bowling ball, the quarter, and so on - which can irritate somewhat, but on the whole the book reads well. A European version would be possible in principle, presumably.
The real issue here is curiosity. Bloomfield's introductory remarks are a familiar lament, but worth emphasis nevertheless. What has happened to our curiosity today? To judge from the success of the popular press, we are insatiably curious about people, but when it comes to curiosity about phenomena, in spite of Tomorrow's World, Horizon and other TV programmes, today's world constantly encourages us to be less curious. When I was a child, a part of growing up was simply taking things to pieces. The two biggest tests, as I recall, were a Sturmey-Archer three-speed, and a pop-up toaster. I did this as much to try to fix them as to find out how they worked. And then there were the glories of radio and the crystal set. It was an era when things went together with nuts and bolts (remember Meccano?) and so could be taken to pieces and put together again. Today the world is no longer like that. Kids spend a lot of their time surfing the web, doubtless an interesting pursuit. But even if they wished to dismantle a radio, or their PC, they would learn almost nothing by so doing. Modern integrated circuitry has seen to that. When the car breaks down, call the AAI So it is that the complexity and the inexpensiveness of so many devices today actively discourage curiosity. In a throw-away society, who cares how it works, or why it's not working? Go out and buy another one!
Bloomfield knows all this, and realises that he has a task on his hands. At the very beginning of his intellectual adventure he needs to equip his students with the tools for the job. More than that: He is saying "Let's have some fun too! This is exciting stuff, so let's really try to find out, let's get used to asking questions about some of the marvellous things around us!" Robert Ehrlich's text is similarly motivated, but his is a book which every physics teacher ought to have. Anyone who has dared to put on demonstrations of physical laws knows well that the most oft-demonstrated law is that of Mr Murphy. One may also have encountered colleagues who question the value of putting hours of effort into the perfection of a demonstration which in front of an audience is going to take only a minute or two. There is no getting away from it: demonstrations demand effort, but when successful can explain in a few seconds a concept that could take very much longer in chalk-and-talk mode. There are over 100 demos in the book, some well known, such as "When to add cream to your coffee", "Deep knee bends on a bathroom scale", and various experiments in optics and magnetism too. The emphasis is on simple apparatus, and the discussion of each demonstration is usually layered: first qualitative, then quantitative/mathematical as necessary, and finally a very useful bibliography for those who would like to follow the development of particular ideas. The sand-filled egg-timer is a good example: the earliest, "proper" discussion of this problem got it wrong, by concluding that there should be no difference at all when the sand is in motion. It was argued that the loss of weight due to the sand actually in mid-air was exactly balanced by the momentum change produced by the sand hitting the bottom. This is actually true, but later authors pointed out that there is an additional effect which makes the measured weight appear greater when the sand is in motion. Like to know why? Buy the book - if you are curious.
Who will buy these books? Ehrlich has aimed well, at an identifiable target. This is a book for people who enjoy such things, but is primarily for professionals. Every physics teacher, from school through to university should have a copy.
Bloomfield has likewise aimed well, but it is not immediately obvious that there is a UK market that parallels his US arts majors. For biological sciences teachers in schools who may be faced with having to teach physics, this could be the perfect introduction because it takes so little for granted. Also if there are university courses in the UK that mix arts with sciences, this would do well for the physics component of that. But whoever you are, if you are curious, or at least willing to have your curiosity aroused, this book could be very enjoyable. It would look good on the coffee table too, because the production is to a very high standard.
Mike Leask is senior physics fellow, St Catherine's College, Oxford.
How Things Work: The Physics of Everyday Life
Author - Louis A. Bloomfield
ISBN - 0 471 59473 3
Publisher - Wiley
Price - £17.99
Pages - 706