Review: Humble Pi

 Humble Pi claims to be a book about math mistakes. It's actually not a book about mistaken math theorems or anything fundamental like that. It's a book about engineering misapplications of math. So the start of the book actually covered lots of material from Epic Engineering Failures and the Lessons They Teach. It's probably not a surprise that a written explanation of the same material done by a top professor in visual format is not very interesting and therefore if that was all the book was I wouldn't label it with a recommended tag.

Fortunately, Matt Parker goes beyond the classics and go into various additional failures, including the common misconception that daylight savings time creates extra heart attacks. It turns out that an analysis at the week level data demonstrates that the weeks that include a changeover time didn't actually have more heart attacks, just that the heart attacks were brought forward into earlier in the week:

It seems the clocks going forward and depriving people of sleep did cause extra heart attacks, but only in people who would have had a heart attack at some point anyway. The heart attack merely happened sooner. And likewise, the clocks going back gave people a rest and bought them a few more days until their heart turned on them. This could be relevant information for a hospital planning its staffing around when the clocks go forward, but it does not mean daylight saving time is net dangerous. (kindle loc 2706)

Then there's a bridge that was built between Germany and Switzerland, both countries being very well known as civil engineering powerhouses. Well, even those countries can occasionally make a mistake:

The ocean is not a neat, flat surface; it’s constantly sloshing around. And that’s before you get to the Earth’s uneven gravitational field, which alters sea heights. So a country needs to make a decision on its sea level. The UK uses the average height of the water in the English Channel as measured from the town of Newlyn in Cornwall once an hour between 1915 and 1921. Germany uses the height of water in the North Sea, which forms the German coastline. Switzerland is landlocked but, ultimately, it derives its sea level from the Mediterranean. The problem arose because the German and Swiss definitions of “sea level” differed by 27 centimeters and, without compensating for the difference, the bridge would not match in the middle. But that was not the math mistake. The engineers realized there would be a sea-level discrepancy, calculated the exact difference of 27 centimeters and then . . . subtracted it from the wrong side. When the two halves of the 225-meter bridge met in the middle, the German side was 54 centimeters higher than the Swiss side. (kindle loc 2988)

The book is surprisingly fun and I enjoyed it. It was definitely worth reading!