Experimental Soft Condensed Matter Group Harvard University, Prof. D. A. Weitz Cool Picture of the Moment

Compression of a gel ball in a glass capillary: The movie shows a poly-acrylamide gel ball that is being pressed through a narrowing glass capillary; the movie is sped up ~10X and the diameter of the narrow end of the gel ball is ~20µm. During the course of the movie the applied pressure is increased from 4psi to 15 psi, causing the gel ball to be pressed deeper toward the narrow part of the capillary. Interestingly, the gel ball is compressed not only radially, but also along the channel direction. The resulting volume change as a function of applied pressure can serve as a measure for the compressive modulus of the gel ball.

For more information contact Hans Wyss.

Past cool pictures...