Light Mircroscopy

• What is the main purpose of a light microscope?

  To magnify small objects for observation
• What are the main parts of a light microscope?

  • Eyepiece lens
  • Objective lens
  • Stage
  • Handle
  • Clip
  • Coarse adjustment knob
  • Fine adjustment knob
  • Lamp
• What is the function of the eyepiece lens in a light microscope?

  It magnifies the image and allows the user to see it
• How many objective lenses are typically found on a light microscope?

  Usually three different objective lenses
• What is the purpose of the stage in a light microscope?

  To support the slide
• What does the coarse adjustment knob do?

  It moves the stage up and down to bring the image into focus
• Why is it important for specimens to be prepared before investigation?

  They need to let light through for clear observation
• What should you do if your specimen is too thick to see clearly?

  You need to take a thin slice of it
• What is the purpose of adding a drop of water or mountant on the slide?

  To secure the specimen in place
• When would you add a drop of stain to your specimen?

  If the specimen is completely transparent or colorless
• What is an example of a stain used to highlight cytoplasm?

  Sosin
• What does methylene blue stain?

  DNA
• How should you place a cover slip on the slide?

  At an angle, lowering it gently to avoid air bubbles
• What is the first step to view a specimen under a light microscope?

  Clip the slide containing the specimen onto the stage
• What should you do after selecting the lowest-powered objective lens?

  Use the coarse adjustment knob to move the stage up
• Why is it important to look down the eyepiece while adjusting the stage?

  To avoid crashing the slide into the lens
• What should you do if you need to see your specimen with greater magnification?

  Swap to a higher-powered objective lens and refocus
• What are the potential issues with using high magnification on a specimen?

  You might not be able to see the whole specimen or focus properly
• What is the process for preparing a specimen for viewing under a light microscope?

  1. Ensure the specimen allows light to pass through.
  2. Place a drop of water or mountant on a clean slide.
  3. Use tweezers to place the specimen on the slide.
  4. Add a drop of stain if necessary.
  5. Place a cover slip at an angle and lower it gently.
• What steps should be followed to view a specimen under a light microscope?

  1. Clip the slide onto the stage.
  2. Select the lowest-powered objective lens.
  3. Use the coarse adjustment knob to move the stage up.
  4. Look down the eyepiece and adjust the stage downwards.
  5. Use the fine adjustment knob for a clear image.
  6. If needed, switch to a higher-powered lens and refocus.
• What is magnification in the context of microscopy?

  Magnification is how many times bigger the image is than its real size.
• How can you calculate the total magnification of a microscope image?

  Total magnification = eyepiece lens magnification x objective lens magnification.
• If the eyepiece lens magnification is 10 and the objective lens magnification is 40, what is the total magnification?

  Total magnification is 400.
• What can you do if you don't know which lenses were used in a microscope?

  You can calculate magnification if you measure the image and know the real size of the specimen.
• What is the formula to calculate magnification using image size and real size?

  Magnification = image size / real size.
• How do you rearrange the magnification formula to find image size?

  Image size = magnification x real size.
• If a specimen is 50 µm wide and viewed under a magnification of x100, what is the width of the image?

  The width of the image is 5000 µm or 5 mm.
• How do you convert from micrometres (µm) to millimetres (mm)?

  To convert from µm to mm, divide by 1000.
• Why is it useful to write numbers in standard form when using microscopes?

  It makes very big or small numbers more manageable.
• How can you express 0.0025 mm in standard form?

  0.0025 mm can be written as $2.5 \times 10^{-3} \text{ mm}$.
• What does the power of 10 represent in standard form?

  The power of 10 represents how many places the decimal point has moved.
• How do you input standard form numbers into a calculator?

  You can use the 'EXP' or 'x10^' button on the calculator.
• What are the steps to calculate the image size from magnification and real size?

  1. Use the formula: image size = magnification x real size.
  2. Fill in the known values.
  3. Remember to convert units if necessary.
• What are the key concepts related to magnification in microscopy?

  • Magnification is the ratio of image size to real size.
  • Total magnification is calculated using eyepiece and objective lens magnifications.
  • Standard form is useful for expressing very small or large measurements.