Microscopes

• There are light and electron microscopes
• A light microscope uses light
• An electron microscope uses electricity
• A light microscope can view living tissue (benefit)
• A light microscope can only magnify up to 1000x (limitation)
• An electron microscope can only view dead tissue (limitation)
• An electron microscope can magnify up to x1,000,000 (benefit)
• Label:

  A) Eye piece lens

  B) Objective lens

  C) Stage

  D) Mirror

  E) Focus wheel

  
• Total magnification = eyepiece lens x objective lens
• total magnification of eye piece lens (x20) and objective lens (x30) is x600
• image size = actual size x magnification
• A cell of 48mm image size with a magnification of x1000 = 0.048mm
• To prepare an onion slide: place the thin piece (epidermis) of onion onto a glass slide and make sure it's flat; add a few drops of iodine to stain the cell, making it more visible; use a mounted needle to slowly lower the cover slip, reducing the chances of air bubbles; View under all objective lens
• Preparing a human cheek cell: Swab inside of cheek with a cotton bud to extract cheek cells; wipe cotton bud in centre of glass slide to transfer; add methylene blue to stain cheek cells; use a mounted needle to slowly cover slip onto glass, preventing air bubbles; view under all objective lens