To view this video please enable JavaScript, and consider upgrading to a web browser that supports HTML5 video Movie S3. Long-exposure image of the contact during stimulation with a square waveform envelope. The sudden change in ultrasonic vibration amplitude leads to a progressive modification of the interfacial friction. Partial squeeze film levitation modulates fingertip friction MichaĆ«l Wiertlewski, Rebecca Fenton Friesen, and J. Edward Colgate PNAS. 2016. DOI: 10.1073/pnas.1603908113 Download Original Video Browse All Videos »