Raindrops start to form in a roughly spherical structure due to the surface tension of water. This surface tension is the "skin" of a body of water that makes the molecules stick together. The cause is the weak hydrogen bonds that occur between water molecules. On smaller raindrops, the surface tension is stronger than in larger drops. As the raindrop falls, it loses that rounded shape and becomes more like the top half of a hamburger bun, flattened on the bottom and with a curved dome top. The shape of a raindrop depends on its size, with small raindrops being spherical, medium raindrops having a hamburger bun appearance, and large raindrops taking on the shape of an open parachute due to the force of air pushing upward and flattening the bottom. Once raindrops reach a certain size, they break apart into smaller raindrops.
So, in summary, the shape of a raindrop is not the classic teardrop shape as commonly believed, but rather varies depending on the size of the raindrop, with smaller raindrops being spherical and larger ones taking on a hamburger bun or parachute-like appearance as they fall through the atmosphere.
