- Home
- Publications
- News
- Ultracold gallery
- Group Videos
- Research
- People/Contact
- Courses/Outreach
- Physics Courses
- Spring 2021 P143
- Spring 2021 P334
- Spring 2020 P143
- Spring 2020 P334
- Spring 2019 P226
- Autumn 2018 P238
- Spring 2018 P226
- Autumn 2017 P452
- Spring 2017 P226
- Fall 2016 P154
- Spring 2016 P334
- Spring 2016 P226
- Spring 2015 P334
- Spring 2014 (ETH Zürich)
- Autumn 2013
- Winter 2013
- Autumn 2012
- Winter 2012
- Spring 2011
- Winter 2010
- Spring 2009
- Autumn 2008
- Spring 2008
- Autumn 2007
- Winter 2007
- Autumn 2006
- Spring 2006
- SMART program
- Physics Courses
- Open Positions
- Collaborative project
- Internal
Undergraduate Student Research
Levitation of Macroscopic Particles by Thermophoretic Force
We demonstrate levitation of micron-sized ice, ceramic, glass and polyethylene particles at low pressure (1-10 Torr) in the presence of a temperature gradient. Under thermophoresis, collisions with more energetic gas molecules from below provide a net upward momentum transfer. Particles initially levitate a few millimeters above a cold plate due to the Knudsen Compressor effect. Particles are then accelerated upwards by the thermophoretic force in the direction from hot to cold in the rarefied gas. In the appropriate pressure regime this allows for stable levitation for up to two hours. Lately we have also succeeded in levitating other materials, including thistle seeds and lint. Our future goals are to levitate water droplets, push levitated particles with a laser, and examine the dynamics behind multi-particle levitation.
The Chicago Maroon reported on our levitation project: Physics Undergraduates Help Discover New Levitation Method.
Levitation of Ceramic Particles
Levitation of Thistle