Asked by: Tony Hersh, Newbury
It’s a question many of us ask when caught in a downpour: is it better to run and get to shelter quicker, or does running mean we encounter more raindrops and get wetter?
The amount of rain striking the top of your head each second depends only on how hard it’s raining. So, although running faster won’t change the rate at which you get wet, it will get you to shelter quicker, minimising your exposure to the rain and keeping you drier.
Meanwhile, as you head for shelter, the front of your body also cuts through rain and gets wet. But the total amount of rain you travel through depends only on the distance between you and shelter, and has nothing to do with your speed.
Things do get more complicated as you add in the effect of wind speed and direction, but as a rule of thumb, the intuitive answer is right: run towards the nearest shelter as fast as possible.
Robert is a science writer and visiting professor of science at Aston University.