Flashback Friday: Physicists explain why it's so hard to walk with a cup of coffee.

Did you know there's an area of physics called "sloshing dynamics"? Although it more often focuses on topics like rocket fuel in tanks, these physicists have applied their knowledge of sloshing dynamics to the common problem of walking with coffee. (Which is, undoubtedly, completely unrelated to the fact that scientists apparently drink the most coffee of any profession.) To explore this problem, they conducted experiments in which people walked at different speeds with varying amounts of coffee in mugs. They found that most spills happen because we are simply moving too quickly given how full our mugs are. This greediness is not because scientists are addicted to coffee, but rather is due to "the particular range of sizes of common coffee cups, which is dictated by the convenience of carrying them and the normal consumption of coffee by humans." In other words, if you don't want to spill your coffee, ...