Department of Energy Argonne National Laboratory Office of Science NEWTON's Homepage NEWTON's Homepage
NEWTON, Ask A Scientist!
NEWTON Home Page NEWTON Teachers Visit Our Archives Ask A Question How To Ask A Question Question of the Week Our Expert Scientists Volunteer at NEWTON! Frequently Asked Questions Referencing NEWTON About NEWTON About Ask A Scientist Education At Argonne Round Raindrops
Name: Praneeth
Status: student
Age: 11
Location: N/A
Country: N/A
Date: 2001

Why are raindrops always round?

Raindrops are not always round. They are "tear-shaped" blunt end down due to air resistance.

Vince Calder


Molecules that are alike tend to stick together. When drops of water are in free-fall -- as is the case with raindrops -- the molecules' mutual attraction for each other pull the water drop into the shape of a tiny sphere because that shape has the smallest surface area that the piece (drop) of water can take on itself.

This is true for any liquid. Tiny drops in free-fall are always round

ProfHoff 362

Praneeth, A drop is round, if it is not falling through the air (in other words, if it is suspended in the air or in another fluid). When falling through the air, the bottom of the drop is flattened somewhat by the air that it is moving through.

However, drops are round because of a property of the physics of liquids called surface tension. A round shape is the easiest to maintain. If you start a mass of liquid out with another shape (like a cube), it will want to round out any corners and become a drop, or if in a container, it will want to take the shape of the container.

David R. Cook
Atmospheric Research Section
Environmental Research Division
Argonne National Laboratory

Dear Praneeth-

Under undisturbed conditions, raindrops would be round, caused by the surface tension of the droplet, but their motion and environment causes changes to their shape. Raindrops form from very small spherical water droplets, and begin to fall to earth due to gravity. This movement causes the raindrops to be more oval-shaped on the bottom, and more flat on top, similar to an English muffin or biscuit. Air currents can distort the shape even further, and sometimes cause the drops to break up into smaller drops.

Wendell Bechtold, meteorologist
Forecaster, National Weather Service
Weather Forecast Office, St. Louis, MO

Click here to return to the Weather Archives

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (, or at Argonne's Educational Programs

Educational Programs
Building 360
9700 S. Cass Ave.
Argonne, Illinois
60439-4845, USA
Update: June 2012
Weclome To Newton

Argonne National Laboratory