Life is short and books are long - if not within the covers, then when referring to how many books there are otut here int he world demanding to be read!
That's why I'm glad this was a short, fun book about physics. I could have happily continued reading had it been longer. It's an easy read and makes concepts quite clear - for the most part. There were a couple of times I had to do a double take, and while I don't for a minute profess to be a physicist, the things seemed off to me. I shall mention those below, but overall, this book was well-written, fun, and entertaining, with a nice sense of humor running through it and plenty of readily understandable explanations about what are, let’s face it, often difficult concepts to get one's mind around.
The book has a series of short sections, starting with asking what physics actually is, and each covers a different physics topic. Nothing important is left out, not even relativity and quantum mechanics, so if you want a basic grounding in physics, this is a great place to begin. It covers: astrophysics, electricity, energy, forces, heat, magnetism, matter, motion, all delivered well and educationally without straying too far into technical jargon or obscure explanations.
I ran into a problem on page 55 in a boxed section discussing an experiment by Dutch philosopher and mathematician Willem Jacob 's Gravesande, who experimented with dropping brass balls onto a smooth clay surface and measuring the depth to which the balls penetrated the clay, deriving a formula from it. Émilie du Châtelet made subsequent use of this, but she gets no mention in this book. The author talks about the brass balls falling at different speeds, but as he points out in this same book, acceleration under gravity is constant regardless of the weight of an object! So speed would seem to be far less relevant than mass in this case? Maybe I'm missing something, but it seemed odd to me.
The other issue I had was on page 92, where the author was discussing inflating balloons. He said that once a balloon is inflated and sealed, the pressure inside equals the pressure outside, but I for the life of me could not see this. The air in the balloon is under pressure - it has to be to inflate the constricting rubber (or whatever) of the balloon skin. If it equaled what was outside, then surely the balloon wouldn't sink to the ground as they typically do, but float at whatever height you set it? Again, maybe I'm missing something here, and maybe it’s purely the weight of the rubber that's causing the balloon to sink rather than the extra weight of the compressed air inside, otherwise it would float, but it seems to me that the pressure inside has to be greater. If it were less, the balloon would rise, surely? The author seems to admit this himself a paragraph or so later when talking about hot air balloons.
But whether this is a mistake of some sort, or whether I'm up a gum tree takes nothing away from the overall quality of the book, which I commend as a worthy and educational read.
