Apparatus and Method

• Microscope: American Optical 100x
• Digital camera: Fuji FinePix S7000; 128Mb memory card will record approximately 1.5 min. of video at 30 frames/sec.
• Software: Tracker (an Open Source Physics Project) was used to analyze the data.
• Particles:
• Latex 1.07 micron diameter polymer, density 1.05 g/ml.
• Fern and Moss spore, approximately 2 micron diameter.
• ink (unknown size).
  
• Liquids: Dynamic Viscosity at 20°C in N·s/m² :
  • H₂0: 1.025*10^-3.
  • Alcohol:  0.248*10^-3.
  • Olive Oil:  81*10^-3.

Measurements: Average square displacement versus time

       where x is the horizontal displacement in time t, a is the radius of the particles, T is the absolute temperature and  is the dynamic viscosity.

Videos lasting approximately 1.5 min. were taken at a rate of 30 per second and analyzed using Tracker. Data was exported into Excel to make graphs of x² vs time, N_A was determined from the slope of the graph.







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