Microscopy - Required Practical

Question 1

How do you use a light microscope to view a prepared slide?

Answer 1

1. Place sample tissue onto a glass slide and stain with a couple of drops of iodine, then place a glass cover slip over the top.
2. Place the prepared slide onto the stage and use the clips to hold the slide into place.
3. Select the lowest power objective lense (usually being 4x).
4. Position the objective lense so it almost touches the microscope slide, by slowly turning the coarse focussing dial.
   - Ensure to look at the microscope from the side whilst adjusting the position of the objective lense. When the objective lense almost touches the slide, stop turning the dial.
5. Whilst looking through the eyepiece, slowly turn the coarse focusing dial so that the distance between the objective lense and the slide is increased.
   - Do this until the cells come into focus.
6. Use the fine focusing dial to bring the cells into a clear focus.

Question 2

How would you calculate the total magnification?

Answer 2

• Multiply the magnification of the eyepiece lense by the magnification of the objective lense.
• E.g: Eyepiece lense = 10x, Objective lense = x4, Total magnification = x40.

Question 3

What would you do if you needed to select a higher power objective lense? (e.g. x10)

Answer 3

• Change the objective lense
• Use the fine focusing dial to bring the cells back into focus.

Question 3

How would you create a magnification scale?

Answer 3

• Place a clear plastic ruler over the stage.
• Measure the diameter of the field view in mm.
• Show this on our drawing using a scale bar
• Also write the magnification on the drawing e.g: x100