We’ve all been there – caught outside without an umbrella as the sky opens up. Whether it’s a light drizzle or a heavy downpour, instinct tells us that running will minimise how wet we get. But is that really true? Let’s take a scientific look at this common dilemma.
You’re out and about, and it starts to rain – and naturally you’ve forgotten your umbrella. Instinctively, you lean forward and quicken your pace. We all tend to believe that moving faster means we’ll spend less time getting wet, even if it means getting hit with more rain as we move forward.
But is this instinct actually correct? Can we build a simple model to find out if speeding up really reduces how wet we’ll get? More specifically, does the amount of water that hits you depend on your speed? And is there an ideal speed that minimises the total water you encounter on your way from point A to point B?
Look from the reference frame of the raindrops. Imagine that instead of falling downwards they are stationary in space and you are moving upwards through them. You cross more en route to your destination if you spend longer.