Microscope Parts and Functions Quiz

Microscope Parts and Functions

• Eyepieces/Ocular Lens: Viewer looks through this lens, located opposite the light source
• Base: Flat structure that supports the microscope
• Stage: Holds and navigates the sample
• Arm: Connects the base to the nosepiece and eyepiece, used for carrying the microscope
• Nosepiece: Holds the objective lenses, can be rotated to select different lenses
• Objective Lenses: Primary magnifying lenses
• Condenser: Controls the light that falls on the sample
• Light Source: Illuminates the sample with transmitted light
• Diaphragm: Controls the amount of light entering the condenser
• Coarse Adjustment Knob: Makes larger movements, used for bringing the objective down to the stage or vice versa
• Fine Adjustment Knob: Makes smaller movements, used for final focusing and small adjustments during imaging

Microscope Care

• Carry the microscope securely with two hands: one under the base, one on the arm
• Keep the microscope upright
• Clean lenses with lens cleaner and lens paper, do not use paper towels or clothing
• Only use the fine-focus knob when using the high-power objective lens
• Remove slides before putting the microscope away
• Store with the low-power objective in place
• Lower the stage before putting the microscope away

Microscopy Procedure

• A. Using the Microscope:
  • Familiarize yourself with the parts of the microscope
  • Turn on the microscope with the ocular lens facing you
  • Start with the low-power objective (4x)
  • Raise the condenser lens to its highest level
  • Cut out letters from newsprint and place them on a slide with a drop of water
  • Cover with a coverslip, avoiding air bubbles
  • Place the slide on the stage, centered and secured with the stage clip
  • Use the coarse adjustment knob to bring the specimen into focus
  • Adjust the light using the base, iris diaphragm lever, or condenser lens
  • Draw the letter under low power
  • Switch to higher powers (10x, 40x) and adjust focus using the fine-focus knob
  • Observe the effect of magnification on the size of the image and the field of view
• B. Preparation of a Wet Mount:
  • Scrape the inside of your cheek with a toothpick
  • Smear the cheek material on a clean microscope slide
  • Add a drop of methylene blue stain
  • Cover with a coverslip and examine under the microscope
  • Draw a single cheek cell
• C. Observation of a Prepared Tissue Slide:
  • Examine a prepared slide under low power
  • Scan the area and select areas for closer observation
  • Switch to higher power and adjust focus using the fine-focus knob
  • Draw what you see
• D. Oil Immersion Lens:
  • Once you have examined the specimen under high power, center the area of interest in the field of view
  • Add a drop of immersion oil on top of the coverslip
  • Carefully move the oil immersion lens into place
  • Use only the fine-focus knob to avoid damaging the slide
  • After examining, swing the lens away and remove the slide, wiping away the oil with lens paper

Compound Microscope

• Uses two convex lenses: ocular lens and objective lens
• Light passing through a convex lens bends and converges at a point, creating an inverted image
• The objective lens creates an inverted image of the specimen, which is then further magnified by the eyepiece, remaining inverted

Post-Discussion Questions

• 1. Total magnification is calculated by multiplying the ocular lens magnification by the objective lens magnification.
  • 7x objective lens = 70x total magnification
  • 15x objective lens = 150x total magnification
  • 20x objective lens = 200x total magnification
• 2. The glass plate placed on top of a specimen is called a coverslip.
• 3. The iris diaphragm controls the amount of light entering the condenser.
• 4. When switching from a low-power objective to a higher-power objective, the working distance between the lens and the coverslip decreases.
• 5. The low-power objective should be used when:
  • Viewing a new slide
  • When the specimen is lost in the field of view under a high-power objective
• 6. The proper way to carry a microscope is to securely hold it with two hands: one on the arm and the other under the base.

Test your knowledge on the various parts and functions of a microscope with this quiz. From the eyepiece to the fine adjustment knob, learn about each component's role in the microscope's operation. Perfect for biology students and enthusiasts alike!