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In this edition I would like to explain why hot water freezes faster than cold water, when put into the freezer. It is a very counter-intuitive observation, it's a paradox. This is called the Mpemba Effect. The effect is named according to Tanzanian high-school student Erasto B. Mpemba who re-discovered the effect while making ice cream back in 1963. The Mpemba Effect is a nice example of how the change of one variable, the temperature, can have unexpected side effects. Most people assume that the difference between a hot glass of water and a cold glass of water is only the temperature. But this is not the case. Just by heating the water we are introducing a range of other variables that have an unexpected effect on the outcome.

"The behavioral revolution in economics and psychology has successfully identified and named close to three dozen biases (my favorite behavioral folk song defines them in verse). I had thought that these biases transcended issues of culture. Indeed, both neoclassical and behavioral economists were united in a belief that cultural variables were of secondary importance when it came to the deep drivers of behavior. But a series of experiments now has me thinking that the underlying heuristics are less universal."

"Benno M. Nigg has become a leading researcher on orthotics - those shoe inserts that many athletes use to try to prevent injuries. And what he has found is not very reassuring. For more than 30 years Dr. Nigg, a professor of biomechanics and co-director of the Human Performance Lab at the University of Calgary in Alberta, has asked how orthotics affect motion, stress on joints and muscle activity. Do they help or harm athletes who use them? And is the huge orthotics industry - from customized shoe inserts costing hundreds of dollars to over-the-counter ones sold at every drugstore - based on science or on wishful thinking? "