Requirements (Instruments, Chemicals & Other):

· Optical or compound microscope (with calibration facility)
· Stage micrometer (for calibration)
· Eyepiece graticule or image analysis software
· Glass slides and cover slips
· Fine powder sample
· Spatula or fine brush
· Dropper and distilled water (for dispersion, if required)
· Tissue paper
· Notebook and pencil

Procedure:

1. Calibrate the microscope using a stage micrometer to determine the value of each eyepiece division in micrometers.
   
2. Focus the microscope properly and record the calibration factor.
   
3. Spread a small, uniform amount of powder sample on a clean glass slide.
   
4. If particles are agglomerated, add a drop of distilled water or dispersing liquid using a dropper.
   
5. Place a cover slip carefully, avoiding air bubbles.
   
6. Place the slide on the microscope stage and focus under low magnification, then switch to higher magnification for measurement.
   
7. Measure the particle diameter using the calibrated eyepiece or digital software.
   
8. Record at least 50–100 readings for accuracy.
   
9. Group the data into size ranges (e.g., 0–10 µm, 10–20 µm, etc.) and note the frequency of particles in each group.
   
10. Plot a histogram or frequency curve of particle size distribution.
    
11. Calculate the mean, median, and mode of the distribution.
    
12. Comment on the distribution type — whether it is narrow, broad, uniform, or skewed.