4D10.10 - Brownian Motion

See paragraph one and two in the procedure section.
See paragraph five in the procedure section.
See paragraph three and four in the procedure section.
See paragraph three and four in the procedure section.
Code Number:
Demo Title:
Brownian Motion
Kinetic Theory
Area of Study:
Heat & Fluids
Video microscope with 100 X lens, Microslides filled with different density Microsphere solutions. Microspheres, Microscope slide and slip cover. Small black & white video camera, barrel lens with 10X objective, attachment with smoke cell, laser or Maglite, matches.

Place the microslide with the desired density of microspheres under the microscope.  Using the 100 power lens you may observe the Brownian motion. 

Poisson Distribution.  THIS WILL TAKE 2 TO 3 DAYS ADVANCED NOTICE:  Prepare a microslide with a high density solution of microspheres.  Set the microslide at an incline for several days or until a Poisson distribution is established in the microslide.  


Put a drop of microspheres ( 1 micron diameter spheres ) onto the microscope slide.  Cover with a slip cover to make a thin even layer.  Place on the microscope and focus.  Small black dots displaying Brownian motion will be easily observable.   It helps to cover the eye pieces of the microscope when operating in the video mode.

A substitute for the microspheres would be to use a dilute solution of milk on a slide.  The globules of fat will show Brownian motion. 


To do Brownian motion with smoke particles you will do the following procedure.  

NOTE: This is much more difficult than using the microspheres and requires constant attention and adjustment.  

Attach the barrel lens to the video camera and then the smoke cell attachment to the barrel lens.  Fill the smoke cell with smoke from a match and illuminate with either the laser or the Maglite.  This will show up fairly well on a TV if you are not very far away, although the contrast will still be fairly poor.  The best way to do this is to video capture a segment of the motion and apply some sharpening and false color, and then project the rendered video.

  • Makito Miyazaki, Yosuke Yamazaki, Yamato Hasegawa, "Analysis of Brownian Motion by Elementary School Students", TPT, Vol. 60, #6, Sept. 2022, p. 478.
  • Se-yuen Mak, "Brownian Motion Using a Laser Pointer", TPT, Vol. 36, # 6, Sept. 1998, p. 342. 
  • Bill Reid, "Viewer for Brownian Motion", TPT, Vol. 29, # 1, Jan. 1991, p. 52. 
  • Haym Kruglak, "Taking a Random Walk on TV", TPT, Vol. 26, # 3, Mar. 1988, p. 157.
  • Sister Martha Ryder, "Brownian Movement", TPT, Vol. 12, # 9, Dec. 1974, p. 574. 
  • Karl D. Stephan, "An Economical Smoke Chamber and Light -Sheet Microscope System for Experiments in Fluid Dynamics and Electrostatics", AJP, Vol. 91, #4, April 2023, p. 316.
  • Philip Pearle, Brian Collett, David Bilderback, Dara Newman, Scott Samuels, "What Brown Saw and You Can Too", AJP, Vol. 78, # 12, p. 1278, Dec. 2010.
  • Joseph Peidle, Chris Stokes, Robert Hart, Melissa Franklin, Ronald Newburgh, Joon Pahk, Wolfgang Rueckner, Aravi Samuel, "Inexpensive Microscopy for Introductory Laboratory Courses", AJP, Vol. 77, #10, Oct. 2009, p.  931.
  • Dongdong Jia, Jonathan Hamilton, Lenu M. Zaman, Anura Goonewardene, "The Time, Size, Viscosity, and Temperature Dependence of the Brownian Motion of Polystyrene Microspheres", AJP, Vol. 75, # 2, p. 111, Feb. 2007.
  • Paul Nakroshis, Matthew Amoroso, Jason Legere, Christian Smith, "Measuring Boltzmann's Constant Using Video Microscopy of Brownian Motion", AJP, Vol. 71, # 6, June 2003, p. 568.
  • Don S. Lemons and Anthony Gythiel, "Paul Langevin's 1908 Paper 'On the Theory of Brownian Motion'", AJP, Vol. 65, #11, Nov. 1997, p. 1079.
  • Haym Kruglak, "Brownian Movement: An Improved TV Demonstration", AJP, Vol. 55, # 10, Oct. 1987, p. 955.
  • Henry Unruh, Jr., Patrick M. Maxton, and Jonathan Schwartz, "Experimental Study of the Brownian Motion of a Harmonically Bound Particle", AJP, Vol. 47, #9, Sept. 1979, p. 827.
  • Robert Stoller, "Viewing Brownian Motion With Laser Light", AJP, Vol. 44, #2, Feb. 1976, p. 188.
  • George Barns, "A Brownian Motion Demonstration Using Television", AJP, Vol. 41, #2, Feb. 1973, p. 278.
  • Noel A. Clark and Joseph H. Lunacek, "A Study of Brownian Motion Using Light Scattering", AJP, Vol. 37, #9, Sep. 1969, p. 853.
  • Richard J. Fitzgerald, "Graphene Membranes’ Anomalous Dynamics", Physics Today, Vol. 69, #11, Nov. 2016, p. 24.
  • Douglas J. Durian, "Ballistic Motion of a Brownian Particle", Physics Today, June 2015, p. 10.
  • Mark G. Raizen, Tangcong Li, "Raizen and Li Reply", Physics Today, June. 2015, p. 11.
  • Mark G. Raizen, Tangcong Li, "The Measurements Einstein Deemed Impossible", Physics Today, Jan. 2015, p. 56.
  • H-16, Freier  & Anderson,   A Demonstration Handbook for Physics,  
  • M- 223, Richard Manliffe Sutton,  Demonstration Experiments in Physics. 
  • A-48, Richard Manliffe Sutton,  Demonstration Experiments in Physics,  p. 463.
  • A-50, Richard Manliffe Sutton,  Demonstration Experiments in Physics,  p. 463
  • A-49, Richard Manliffe Sutton,  Demonstration Experiments in Physics,  p. 463
  • A-51, Richard Manliffe Sutton,  Demonstration Experiments in Physics,  p. 464
  • Eli Barkai, Yuval Garini, Ralf Metzler, "Strange Kinetics of Single Molecules in Living Cells", Physics Today, Aug. 2012, p. 29.
  • "An Optical Speed Trap for Brownian Motion", Physics Today, July 2010, p. 19.
  • Wallace A. Hilton, "Brownian Motion", A Potpourri of Physics Teaching Ideas - Heat and Fluids, p. 116.
  • R. W. Pohl, "The Free Movement of Molecules in a Liquid: The Brownian Movement", Physical Principles of Mechanics and Acoustics, p. 152.
  • "Experiments with Camphor", The Boy Scientist, p. 150.
  • Reese Salmon, Candace Robbins, Kyle Forinash, "Brownian Motion Using Video Capture", Eur. J. Phys. Vol. 23, 2002, p. 249.
  • Kenneth Lonnquist, "Experiments in Quantum Mechanics - Brownian Motion", Physics Laboratory, Physics Department, Colorado State University. 
  • Little Shop of Physics, "The Motion of Molecules", Colorado State University. 
  • Richard E. Berg, "HINTS: Simplified Brownian Motion Demonstration", PIRA Newsletter, Vol. 3, # 5, September 10, 1988, p. 3.
  • Ron Hipschman, "Brownian Motion (Molecular Buffering)", 1980 Exploratorium Cookbook II, Recipe # 128.
  • "Brownian Movement Smoke Cell", EMD / A Division of Fisher Scientific, 92/93 Physics & Technology, p. 106.
  • "Brownian Movement Apparatus", Central Scientific Company, 1990.
  • "Instruction for Cenco Cat. # 71268  Brownian Movement Viewer", Central Scientific Company, 1990.
  • "Brownian Movement", Central Scientific Company, 1960.
  • A. Mason Turner, "E.M.E. Molecular Motion Demonstrator", Study Guide, 1975.
  • Griffin & George, " Whitley Bay Smoke Cell XCU-300-T", Instructions.
  • Ron Hipschman, "Brownian Motion (Molecular Buffering)", 1980 Exploratorium Cookbook II, Recipe # 127.
  • Yaakov Kraftmakher, "7.20, Demonstrations with a Microscope", Experiments and Demonstrations in Physics, ISBN 981-256-602-3, p. 493.
  • W. Bolton, "Brownian Motion", Book I - Properties of Materials, Physics Experiments and Projects, 1968, p. 30.
  • Tap-L conversation with Gerald Zani, Aug 2005.
  • Tap-L conversation with Sam Sampere, Sep 2007.

Disclaimer: These demonstrations are provided only for illustrative use by persons affiliated with The University of Iowa and only under the direction of a trained instructor or physicist.  The University of Iowa is not responsible for demonstrations performed by those using their own equipment or who choose to use this reference material for their own purpose.  The demonstrations included here are within the public domain and can be found in materials contained in libraries, bookstores, and through electronic sources.  Performing all or any portion of any of these demonstrations, with or without revisions not depicted here entails inherent risks.  These risks include, without limitation, bodily injury (and possibly death), including risks to health that may be temporary or permanent and that may exacerbate a pre-existing medical condition; and property loss or damage.  Anyone performing any part of these demonstrations, even with revisions, knowingly and voluntarily assumes all risks associated with them.