#RAINDROP FALLING ON MY WINDOW SKIN#

Titan, too, has rivers, lakes, valley networks and rain, even though the fluid involved is quite different - liquid methane instead of water. We know similar processes are also at work elsewhere. It shapes both our skies and our landscape, carving valleys while filling rivers and lakes. If we get a different signal from each orientation, we must be measuring flattened drops, which are much bigger and indicate heavier rain.Rainfall is one of the defining characteristics of our weather, with amounts varying dramatically from one region to another. If we get the same signal from vertical and horizontal waves, we know we are measuring spherical drops, which must be small drizzle. The best radar can send these radio waves oriented vertically and horizontally, known as polarisation. This is also useful when we measure the weather with radar that sends a beam of radio waves into a cloud and measures how the waves bounce back. With a maximum size set for the raindrops, we can use this information in the simulations that give us our weather forecasts and help us predict how much it rains. There are two main reasons this is important. Distorted by the wind, it starts flapping around and is eventually ripped to shreds. I like to think of this like throwing a bouncy castle out of a plane. The biggest ever measured raindrops are around this size. At this point the surface tension tends to fail completely and the droplet is ripped apart into dozens of smaller droplets. Now, the droplet falls much faster and gets so flat that is ends up stretched thin and domed like a parachute, where the wind pushes it up. It has a surface area 2500 times our first drizzle droplet, but a mass 125 000 times bigger. Maybe rather than a football, you could imagine this like a half inflated giant beach ball. The exact opposite of what most people expect. This increase in drag force pushing on the underside of the drop, combined with the reduction in the surface tension’s ability to squeeze the drop into shape, means that the drop ends up with a flat bottom and broad domed top. The Real Shape of Raindrops via NatureVolve April 29, 2020 It’s the same thing that makes a skydiver’s face look funny when they jump out of a plane. It also falls faster, and so it has wind rushing past it pushing on the bottom - this is known as drag force. So the mass has become more important, and the surface tension finds it less able to squeeze into a perfect sphere. Its surface area is 400 times that of the drizzle, but its mass is 8000 times bigger. What about a much bigger droplet, around two millimetres across? This is a true rain drop.

#RAINDROP FALLING ON MY WINDOW SKIN#

The strong skin on the surface squeezes it into a near perfect sphere. Think of a droplet like a well inflated football. This means they fall slowly, and surface tension squeezes them into near perfect spheres. Since they are small, they have a lot of surface area compared to their mass. These droplets are around one tenth of a millimetre across. Let’s start with the smallest droplets, drizzle the stuff you find when you think you can get away without a raincoat, but half an hour later, you realise you’re soaked and hadn’t noticed. In fact, unlike both my daughters' ideas, if anything, raindrops are short and fat, not tall and thin. But this is because of motion blur, it’s not the actual shape of the raindrop. When we watch rain out of the window or on TV, just like my eldest daughter says, we see it as vertical streaks, or diagonal streaks if there is some strong wind. Unfortunately, both my daughters were wrong. She said when you look at rain, that’s what it really looks like. The first was a teardrop, with a straight point this time, and the second was just a nearly vertical line. My 6 year old drew a teardrop with a curly top, she took a few goes to get the curl just to her liking. Phil Rosenberg 5 min The real shape of rain droplets in all sizes may surprise you.ĭo you know what shape a raindrop is? I asked my 10 year old and 6 year old daughters to draw what they thought a raindrop looked like – at least they get a bit of science during their COVID-19 home-schooling. Most people do not draw raindrops that look anything like their true form. Most people don't realise the real shape of raindropsĮveryone can draw a raindrop, right? Perhaps not. Most people don't realise the real shape of raindrops.

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Raindrop falling on my window