Investigate the effect of particles settling out and interacting with the bottom of the microscope slide.

Our samples are from Bangs Labs.  Functionalized silica spheres.  

[[https://wiki.uchicago.edu/download/attachments/154371469/PDS%20702%20Web.pdf?version=1&modificationDate=1547566659000&api=v2|Example data sheet.]]

[[https://wiki.uchicago.edu/download/attachments/154371469/TechNote%20206%20Web.pdf?version=1&modificationDate=1547566682000&api=v2|Bangs Labs Technote.]]

For our spheres the maximum settling velocity in water at room temperature should go as

Vm=5.448x10−5(ρs−1)d2Vm=5.448x10−5(ρs−1)d2 {FIXME $V_{m} = 5.448x10^{-5} (\rho_{s} - 1) d^{2}$ .
VmVm {FIXME $V_{m}$  = maximum settling velocity in (cm/sec).
ρsρs {FIXME $\rho_{s}$  = sphere density (g/cm3).
d2d2 {FIXME $d^{2}$  = mean diameter of sphere (μm).
Data for our microspheres.  Assume a drop depth of 0.01" (0.0254cm).

| Particle Diameter    (μm)  | VmVm {FIXME $V_{m}$    (cm/s)  | Settling Time    (s)  | Settling Time    (m)  |
| 0.57  | 1.77e-5  | 1435  | 23.9  |
| 0.96  | 5.02e-5  | 506  | 8.4  |
| 1.54  | 1.29e-4  | 196.9  | 3.3  |
| 3.17  | 5.47e-4  | 46.4  | 0.77  |
| 4.89  | 1.30e-3  | 19.5  | 0.33  |
| 8.37  | 3.82e-3  | 6.7  | 0.11  |