Light microscopy

• What is the main purpose of a light microscope?

  To see really small things
• What are the main parts of a light microscope?

  • Eyepiece lens
  • Stage
  • Focusing knobs
  • Objective lens
  • Clip
  • Lamp
• What does the eyepiece lens do in a light microscope?

  It allows viewing the image in detail
• What is the function of the stage in a light microscope?

  It supports the slide below
• How do focusing knobs work in a light microscope?

  They move the stage to focus the image
• How many objective lenses are usually found on a light microscope?

  Three different objective lenses
• What is the purpose of the clip on a light microscope?

  It holds the slide in place
• What role does the lamp play in a light microscope?

  It shines light through the slide
• What are the steps to prepare a specimen for viewing under a light microscope?

  1. Take a thin slice of the specimen
  2. Place a drop of water on a clean slide
  3. Use tweezers to place the specimen on the slide
  4. Add a drop of stain if necessary
  5. Lower a cover slip carefully
• Why might a stain be added to a specimen?

  To highlight structures or tissues
• What should you avoid when lowering a cover slip onto the slide?

  Trapping bubbles under the cover slip
• What is the first step in viewing a specimen using a light microscope?

  Clip the slide onto the stage
• Which objective lens should be selected first when viewing a specimen?

  The lowest power objective lens
• What is the purpose of the coarse adjustment knob?

  To move the stage up and down
• What should you do after moving the stage down to focus the specimen?

  Use the fine adjustment knob for clarity
• What happens if you want to make the image bigger?

  Use a higher power objective lens
• What should you do once you are satisfied with the view of your specimen?

  Make a scientific drawing of the specimen
• What is a potential issue with high magnification?

  You may not see the whole specimen
• Why can it be difficult to focus at high magnification?

  Because of the narrow field of view
• What type of microscope is mentioned in the text?

  Light microscope
• What are the key considerations when using a light microscope?

  • Start with the lowest power objective
  • Adjust focus carefully
  • Be cautious with high magnification
  • Make clear scientific drawings
• What is magnification in microscopy?

  How many times bigger the image is
• How do you calculate total magnification?

  Eyepiece lens magnification × objective lens magnification
• What is the total magnification with eyepiece ×10 and objective ×40?

  400
• What do you need to measure to calculate magnification?

  The image size and real size of the specimen
• What is the formula for magnification?

  magnification = image size / real size
• If the image size is 8 mm and real size is 0.02 mm, what is the magnification?

  400
• What should be done if image size and real size have different units?

  Convert them to the same units first
• How do you find the real size using the formula triangle?

  Image size ÷ magnification
• If the image width is 3 mm and magnification is ×100, what is the real width?

  0.03 mm
• What is standard form used for?

  Writing very big or small numbers simply
• In standard form, what does 'A' represent?

  A number between 1 and 10
• What does 'n' represent in standard form?

  The number of decimal places moved
• How do you write 0.0025 mm in standard form?

  2.5 × 10⁻³
• What is important to check in magnification equations?

  Units must be the same
• If a cheek cell is viewed at ×40 magnification and is 2.4 mm wide, what is the real width in μm?

  60 μm