Calculating pi with darts

I love this one. Really, it's maths not physics, but there is a bit of experimental physics creeping in at the fringes when the experimenters realize that the first method is biased. The second method is much better designed.  Regrettably, pi-day (March 14th, 2015, or 3.14.15) only works if you use the US system of […]

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Check those approximations

A common technique in physics is 'modelling'. This is about constructing a description of a physical phenomenon in terms of physical principles. Often these can be encapsulated with mathematical equations. For example, it's common to model the suspension system of a car as two masses connected by springs to a much larger mass. Here, the […]

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Password entropy

As part of some 'NetSafe' training, I was shown this lovely xkcd cartoon http://xkcd.com/936/ .   Password entropy. That's a good way of putting it. The statistical mechanics definition of entropy would be k ln W, where k is Boltzmann's constant, W is the number of permutations possible, and ln is 'the natural logarithm'. Higher […]

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When stationary is fast

One of the great lines on the cult BBC show 'Red Dwarf' goes (approximately, from memory) like this: Can't you go any faster, like so we're not being overtaken by stationary objects? I'm sure my youngest sister would be able to correct the wording, and tell me immediately which episode it's from, who says it […]

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