Faced with $2.99, your brain reads the leftmost digit first and files the price closer to 2 than to 3. This 'left-digit effect' was measured by researchers Manoj Thomas and Vicki Morwitz in 2005. It even shows up in the US used-car market, where prices drop sharply each time the odometer crosses a 10,000-mile mark. To compare prices fairly, round up in your head.
Chlorine on its own is fairly gentle. But when it combines with urine, sweat and other grime from swimmers, it forms chloramines, which cause stinging eyes and that classic 'chlorine smell'. A well-kept pool barely smells at all. Shower before you swim and never pee in the water.
Muscle mass slowly shrinks with age, putting independence at risk. But in 1990, a study had nursing home residents aged 86 to 96 train their legs for eight weeks: their strength more than doubled. Muscle responds to training at any age. Getting up from a chair without using your hands is already an exercise.