microscopes

• What should you be able to do by the end of the video on using an optical microscope?

  Describe how to use an optical microscope to look at cells on a prepared microscope slide
• Why is it important to learn the details of using an optical microscope?

  Because it could come up in the exam as a six mark essay question
• What is the main part of the optical microscope where the slide is placed?

  The stage
• What is the function of the lamp in an optical microscope?

  To provide light that passes up through the microscope slide
• What is used in some optical microscopes instead of a lamp?

  A mirror
• What are the objective lenses used for in an optical microscope?

  To magnify the image of the specimen
• How many objective lenses do most optical microscopes have?

  Three
• What are the typical magnifications of the objective lenses?

  Four times, ten times, or forty times
• What is the magnification of the eyepiece lens?

  Ten times
• What are the two focusing dials on an optical microscope?

  The coarse focusing dial and the fine focusing dial
• What is the first step to use an optical microscope to view a prepared slide?

  Place the slide onto the stage and use the clips to hold it in place
• What should you select first when using an optical microscope?

  The lowest power objective lens
• How do you position the objective lens when using an optical microscope?

  Turn the coarse focusing dial until it almost touches the microscope slide
• Why is it important to look at the microscope from the side while adjusting the objective lens?

  To avoid damaging the slide
• What should you do after positioning the objective lens close to the slide?

  Look down through the eyepiece and slowly turn the coarse focusing dial
• What is the purpose of the fine focusing dial?

  To bring the cells into a clear focus
• How do you calculate the total magnification of a microscope?

  Multiply the magnification of the eyepiece lens by the magnification of the objective lens
• What is the total magnification when using a ten times eyepiece lens and a four times objective lens?

  $40 \text{ times}$
• What should you do after achieving focus with the lowest power objective lens?

  Select a higher power objective lens and adjust the fine focusing dial
• What can you typically see when looking at animal cells under an optical microscope?

  The nucleons, cytoplasm, and cell membrane
• What can you typically see when looking at plant cells under an optical microscope?

  The cell wall, cytoplasm, and nucleus
• What additional structures might be visible in plant cells under a light microscope?

  The vacuole and chloroplasts
• What should be included in a drawing made from observations using an optical microscope?

  • Clear labeled drawing of cells
  • A magnification scale
  • Measurement of the diameter of the field of view in millimeters
  • A scale bar indicating magnification (e.g., 100 times)
• Where can students find questions related to the required practical on using an optical microscope?

  In the vision workbook linked in the video