Required Practical 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?

  It illuminates the microscope slide
• What do some optical microscopes use instead of a lamp?

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

  They magnify the specimen being viewed
• How many objective lenses do most microscopes have?

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

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

  Ten times
• What is the purpose of the coarse focusing dial?

  To adjust the distance between the lens and slide
• Why should you look at the microscope from the side while adjusting the objective lens?

  To avoid damaging the slide
• What should you do after placing the slide on the stage?

  Select the lowest power objective lens
• How do you bring the cells into focus after selecting the lowest power objective lens?

  Use the coarse focusing dial
• 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?

  $40 \text{ times}$
• What should you do after selecting a higher power objective lens?

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

  Nucleus, cytoplasm, and cell membrane
• What additional structures can be seen in plant cells under an optical microscope?

  Cell wall, vacuole, and chloroplasts
• What should you include in your drawing of cells?

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

  Measure the diameter of the field of view
• What should you do to show the magnification on your drawing?

  Write the magnification, e.g., 100 times
• Where can you find questions on this required practical?

  In the vision workbook
• Why is it important to use a pencil for labeling drawings?

  It allows for clear and precise labeling
• What are the limitations of detail visible under an optical microscope?

  Only limited structures can be seen clearly
• What types of cells can be observed under an optical microscope?

  Animal and plant cells
• What is the process for adjusting the light source in an optical microscope?

  Adjust the lamp or mirror as needed
• Why is it significant to view from the side while adjusting lenses?

  To prevent damage to the slide
• How do you measure the diameter of the field of view?

  Use a clear plastic ruler over the stage
• What is the significance of including a scale bar in drawings?

  It provides a reference for size