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.
For our spheres the maximum settling velocity in water at room temperature should go as
Vm=5.448×10−5(ρs−1)d2Vm=5.448×10−5(ρs−1)d2 {
$V_{m} = 5.448x10^{-5} (\rho_{s} - 1) d^{2}$ .
VmVm { $V_{m}$ = maximum settling velocity in (cm/sec).
ρsρs { $\rho_{s}$ = sphere density (g/cm3).
d2d2 { $d^{2}$ = mean diameter of sphere (μm).
Data for our microspheres. Assume a drop depth of 0.01“ (0.0254cm).
| Particle Diameter (μm) | VmVm { $V_{m}$ (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 |