Microscopy Calculations, Microscope Components, and Course Administration Guide

Objective Magnifications and Field of View Calculations

• Standard Microscope Objective Magnification Values:

  • Scanning Objective Magnification: $4\times$

  • Low Power Objective Magnification: $10\times$

  • High Power Objective Magnification: $40\times$ (There is no "medium" objective lens)

  • Oil Immersion Objective Magnification: $100\times$

• General Formula for Field of View (FOV) Conversion:   $\text{FOV}_1 \times \text{Mag}_1 = \text{FOV}_2 \times \text{Mag}_2$

  • $\text{FOV}_1$: Field of view diameter of the reference objective lens.

  • $\text{Mag}_1$: Magnification rating of the reference objective lens.

  • $\text{FOV}_2$: Field of view diameter ($x$) of the objective lens being calculated.

  • $\text{Mag}_2$: Magnification rating of the objective lens being calculated.

• Key Magnification Rule:

  • Always use the objective lens magnification ($4\times$, $10\times$, $40\times$, or $100\times$) when solving field of view equations. Do not use total magnification.

• Example Calculation 1: Field of View for Scanning Objective

  • Given Parameters:

  • Field of view of Low Power Objective ($\text{FOV}_{\text{low}}$): $8\,\text{mm}$

  • Magnification of Low Power Objective ($\text{Mag}_{\text{low}}$): $10\times$

  • Magnification of Scanning Objective ($\text{Mag}_{\text{scan}}$): $4\times$

  • Equation Setup:     $\text{FOV}_{\text{scan}} \times \text{Mag}_{\text{scan}} = \text{FOV}_{\text{low}} \times \text{Mag}_{\text{low}}$     $x \times 4 = 8\,\text{mm} \times 10$     $4x = 80$

  • Solution:     $x = \frac{80}{4}$

• Example Calculation 2: Field of View for Oil Immersion Objective

  • Given Parameters:

  • Field of view of Low Power Objective ($\text{FOV}_{\text{low}}$): $8\,\text{mm}$

  • Magnification of Low Power Objective ($\text{Mag}_{\text{low}}$): $10\times$

  • Magnification of Oil Immersion Objective ($\text{Mag}_{\text{oil}}$): $100\times$

  • Equation Setup:     $\text{FOV}_{\text{oil}} \times \text{Mag}_{\text{oil}} = \text{FOV}_{\text{low}} \times \text{Mag}_{\text{low}}$     $x \times 100 = 8\,\text{mm} \times 10$     $100x = 80$

  • Solution:     $x = \frac{80}{100} = 0.8\,\text{mm}$

• Relationship Between Magnification and Field of View:

  • The field of view diameter decreases as the magnification of the objective lens increases.

  • The oil immersion lens ($100\times$) has a significantly smaller field of view ($0.8\,\text{mm}$) compared to lower magnification objectives because the image is magnified to a greater degree.

Field of View Area Calculations

• Relationship Between Field of View and Radius:

  • The field of view diameter ($d$) spans the entire circular viewing field from one edge to the opposite edge.

  • Radius ($r$) is defined as exactly half of the field of view diameter:     $r = \frac{\text{FOV}}{2}$

• Mathematical Formula for Area of Field of View:   $\text{Area} = \pi \times r^2$

  • Value of Pi ($\pi$): $3.14$

  • Radius ($r$): Half of the field of view diameter.

• Step-by-Step Area Calculation Example:

  • Calculated Scanning FOV (Diameter): $0.8\,\text{mm}$

  • Compute Radius ($r$):     $r = \frac{0.8\,\text{mm}}{2} = 0.4\,\text{mm}$

  • Compute Area:     $\text{Area} = 3.14 \times (0.4\,\text{mm})^2$     $\text{Area} = 3.14 \times 0.16\,\text{mm}^2 = 0.5024\,\text{mm}^2$

• Alternative FOV Radius Calculation Example:

  • If a given field of view diameter is $5\,\text{mm}$, half of that value serves as the radius $r$ ($2.5\,\text{mm}$, stated as $3.5\,\text{mm}$ in class discussion).

  • Plug the radius value directly into the area formula:     $\text{Area} = \pi \times r^2$

• Common Computational Mistakes:

  • Forgetting to square the radius value ($r^2$) when calculating area (e.g., failing to square $0.4$ to get $0.16$).

  • Using the entire field of view diameter instead of dividing by $2$ to get the radius.

Microscope Components and Operational Controls

• Stage Positioning:

  • Stage Control: The physical component used to move the microscope stage around to reposition a slide.

• Light Intensity and Contrast Regulation:

  • Rheostat: Controls the electrical intensity of the light source.

  • Diaphragm (Iris Diaphragm): Controls the physical aperture opening to adjust the quantity of light reaching the specimen through the condenser.

Study Strategies and Academic Administration

• Recommended Study Practices:

  • Study continuously every week rather than waiting until the last minute before lab exams.

  • The class meets twice per week; material should be reviewed between every class session.

  • Ask questions immediately during class sessions when confused to avoid making mistakes on exams.

• Office Location and Communication:

  • Office Location: 2nd Floor, Room 222J (listed in course syllabus).

  • In-person office visits are preferred over back-and-forth emails, as complex course material is difficult to clarify through typing.

• Attendance Tracking:

  • Scantrons are collected and cross-referenced to monitor student attendance in class.

Technical Issues with Canvas and Enrollment Support

• Canvas Access and Technical Glitches:

  • Students experienced login errors on laptop computers, encountering repeated login and logout error screens.

  • The Canvas mobile application restored course access for some students while laptop web browser access remained non-functional.

  • Students reported paying for virtual labs online the prior evening despite course access issues.

• Roster and Enrollment Discrepancies:

  • Technical errors led to actively attending students being marked as "inactive" on the official class roster despite not being dropped by the instructor.

  • System disruptions may be related to institutional hacking incidents from the previous semester.

  • Resolution: Students displaying inactive status should visit the Admissions office to verify enrollment.