A century after Albert Einstein said we would never be able to observe the instantaneous velocity of tiny particles as they randomly shake and shimmy (in so-called Brownian motion), physicist Mark ...

Then the average speed over that interval is 2 m/s and you’d probably agree that is a better approximation to what we mean by the instantaneous velocity of the object at that point.

Here, we report the measurement of the instantaneous ballistic velocity of Brownian nanocrystals suspended in both aqueous and organic solvents.

Instantaneous rates of change - Higher When a relationship between two variables is defined by a curve it means that the gradient, or rate of change, is always varying.

Arthur L. Foley, A Photographic Method of Finding the Instantaneous Velocity of Sound Waves at Points near the Source, Proceedings of the National Academy of Sciences of the United States of America, ...

Despite extensive attempts, researchers had previously been unable to measure the velocity of particles as they bounce off each other and the molecules of the fluid in which they are suspended.