1: microscopes

• What should you be able to do by the end of the video?

  Describe how to use an optical microscope
• Why is it important to learn the details of using an optical microscope?

  It could come up in a six mark essay
• 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 illuminate 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 slide
• How many objective lenses do most microscopes have?

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

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

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

  Coarse and fine focusing dials
• What is the first step to use an optical microscope to view a slide?

  Place the slide onto the stage
• Why should you select the lowest power objective lens first?

  To avoid damaging the slide
• How do you position the objective lens when starting to view a slide?

  It should almost touch the slide
• What should you do while adjusting the position of the objective lens?

  Look at the microscope from the side
• What should you do after positioning the objective lens?

  Look down through the eyepiece
• What is the purpose of the fine focusing dial?

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

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

  Forty times
• What should you do after selecting a higher power objective lens?

  Adjust the fine focusing dial again
• What can you see when looking at animal cells under an optical microscope?

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

  Cell wall, cytoplasm, and nucleus
• What should you include in your drawing of cells viewed under a microscope?

  A magnification scale and labels
• How do you create a magnification scale for your drawing?

  Measure the diameter of the field of view
• What should you write on your drawing besides the scale?

  The magnification used
• Where can you find more questions on this required practical?

  In the vision workbook
• How does the use of a mirror differ from a lamp in optical microscopes?

  A mirror reflects light, while a lamp emits light