1. Microscopic Measurement Q: How do you measure the size of a microscopic specimen? A: You will get a close estimation using the following technique…

2. Step 1 – Measure diameter of FOV Use a clear ruler with a mm scale to measure the diameter of your field of vision (FOV) at low power. – The FOV is estimated to be 5.0 mm in diameter in the picture shown. – No specimen yet! – Convert to micrometers… 1.0 mm = 1,000 micrometers The FOV is 5,000 micrometers!

3. Step 2 – Estimate specimen’s fraction of the FOV Remove the ruler. Bring your specimen into focus. Estimate the fraction of the FOV the specimen covers. – Is it ½? Is it ⅓? Is it ¾? Use your best judgment.

4. Step 3 - Restate fraction as a decimal Simply divide numerator by the denominator ⅓ = 1 divided by 3 =.3 (repeating)

5. Step 4 – Multiply decimal by FOV! The final step is to multiply the decimal you calculated by the diameter across the FOV you measured..3 X 5,000 micrometers = 1,500 micrometers Your answer should always be reported in micrometers!

6. Sample Problem FOV = 3.5 mm… = 3,500 micrometers Specimen = ½ FOV… = 0.5 (as a decimal) 1,750 micrometers 0.5 X 3,500 micrometers = 1,750 micrometers