Thanks to this process, the average raindrop that actually makes it to your head is only around 1 to 2 mm across. When the droplets get larger than this (at around 5 mm), the air pressure will ultimately overcome the surface tension of the water completely and the raindrop will split apart.Īs the drop continues to fall, it can continue to grow or shrink as it bumps into and absorbs or is broken apart by other droplets. For very large droplets, it can even start to look something like a jellyfish bell, with this usually happening when a raindrop reaches around 4 mm across. Thus, contrary to the popular perception of a teardrop shaped raindrop, thanks to the various pressures the water drop is subjected to as it falls to the ground, the raindrop actually tends to look sort of like a kidney bean or the top of a hamburger bun. This causes the bottom of the drop to flatten out, while the top retains its rounded shape. When this happens, the surface tension of the water that keeps the drop more or less spherical is partially overcome by the airflow pressure on its lower surface as it falls. Ultimately the water drop will become large enough to fall to earth. As the water drop is buffeted around in the air, it collides with other drops, and these small drops coalesce into larger and larger droplets. These tiny droplets, usually between 0.001 and 0.005 mm in diameter, at first form a nearly spherical shape thanks to the relatively strong cohesive forces between the water molecules. Called condensation nuclei, little particles in the air, from dust, smoke or even salt, sit at the center of the tiny droplets that begin to form in a cloud. Raindrops are more than just water the vapor in a cloud has to have something to condense around, without which there would be no rain. To begin with, let’s talk a little about how raindrops actually form.

So why can’t raindrops grow to arbitrarily large sizes? It is unknown, however, if these bad boys ever reached the ground at that size. penny, the largest raindrops ever recorded, between 8.8 mm and 1 cm, were observed by scientists in the clouds above Brazil (1995) and the Marshall Islands (1999).

Would it be possible to have a single raindrop that contains gallons of water?Īt only about half as wide in diameter as a U.S.

Raindrop shape definition