Microscopy Essentials Quiz

Microscope Anatomy

• A microscope is a powerful tool used to observe tiny objects not visible to the naked eye.

Microscope Timeline

• 1000 CE: First vision aid, a "reading stone" (glass sphere) used for magnification.
• 1284: Salvino D'Armate invented the first wearable eyeglasses.
• 1590: Zacharias and Hans Janssen experimented with multiple lenses in a tube, observing magnified objects. This was a precursor to the compound microscope.
• 1665: Robert Hooke observed "pores" or "cells" in cork using a microscope.
• 1674: Anton van Leeuwenhoek built microscopes with single lenses, enabling observations of bacteria, blood, yeast, and insects. His lenses magnified up to 270 diameters.
• 1830: Joseph Jackson Lister reduced spherical aberration in microscopes by combining weak lenses.
• 1872: Ernst Abbe developed a mathematical formula defining the Abbe sine condition, enabling maximum resolution. This impacted microscope design greatly.
• 1903: Richard Zsigmondy invented the ultramicroscope, able to view objects smaller than the wavelength of light..
• 1931: Ernst Ruska co-invented the electron microscope, making it possible to view objects as small as atoms.
• 1932: Frits Zernike created the phase-contrast microscope for visualizing colourless and transparent specimens.
• 1981: Gerd Binnig and Heinrich Rohrer developed the scanning tunneling microscope, giving three-dimensional images at the atomic level.

Microscope Parts and Functions

• Eyepiece/ocular lens: The lens you look through, usually 10x or 15x magnification.
• Arm: The part connecting the base to the head and eyepiece, for carrying.
• Stage Clips: Metal clips holding the slide in place on the stage.
• Coarse Adjustment Knob: A larger knob to roughly focus the microscope. Moves the stage or body tube up and down to focus the specimen.
• Fine Adjustment Knob: A smaller knob for fine-tuning focus after using the coarse adjustment. Moves the stage slightly to sharpen the image.
• Draw Tube: The tube connecting the eyepiece to the microscope body.
• Revolving Nose Piece: Holds objective lenses and rotates to change magnification.
• Objective Lenses: Lenses closest to the specimen providing varying magnification (e.g., 4x, 10x, 40x, 100x).
• Stage: A flat platform holding the slide.
• Diaphragm: A rotating disk with different-sized holes, adjusting the light intensity and the cone projected on the slide.
• Illuminator: The light source typically at the microscope base.
• Base: The bottom providing stability, housing the illuminator and electrical components.

How to Handle a Compound Microscope

• Turn the revolving nosepiece to the lowest power objective (e.g., 4x).
• Place the microscope slide on the stage and fasten with clips.
• Look at the objective lens and stage from the side and turn the coarse adjustment knob until the stage moves upward. Move the stage far enough to avoid hitting the coverslip.
• Look through the eyepiece and move the focus knob until the image comes into focus.
• Adjust the condenser and light intensity to get the best light amount.
• Move your slide around to get the sample in the center of view.
• Use the focus knob to re-focus the sample and adjust light intensity.
• When finished with the lowest power, you can change objectives and might need to re-adjust focus and light intensity.
• Lower your stage and rotate to the lowest-power lens.
• Remove the slide.

Microscope Terms

• Magnification: The factor a microscope enlarges the image, calculated by multiplying objective lens magnification by eyepiece magnification.
• Resolution: The ability to distinguish two separate points as distinct, determining detail and clarity.
• Illumination: The light source used to illuminate the specimen (built-in light, mirror, or external).