microscopes

• a light microscope has many advantages like how it is cheap, portable, samples can be living or dead and that sample preparation is simple however there is less magnification

  
• eyepiece x objective lens= magnification
• Electron Microscope has an advantage of higher magnification but has multiple disadvantages such as less portable, expensive to buy, specimens have to be dead, sample prep is complex higher magnification but has multiple disadvantages such as less portable, expensive to buy, specimens have to be dead, sample prep is complex

  
• How to use a light microscope?

  1.Use focussing wheel to put stage at highest position

  2.Place slide onto stage and use clips to secure it

  3.Starting with the low power objective, look down into eyepiece and get image to focus using focussing wheel

  4.Change to medium power objective lens and use the foccusing wheel to focus the image

  5.Repeat with high power objective lens. Make sure use always focus stage downwards otherwise lens may break the slide
• Looking at plant cells with onion


  1.Cut the small piece from an onion using scissors

  2.Use forceps to peel a small piece of thin skin from the inside of an onion

  3.Put one drop of iodine on the center of a clean microscope slide and put the onion skin into the iodine and spread it out flat

  (Staining allows more detail of the cell to be seen)

  4. Gently lower a coverslip onto the onion skin

  5.Examine under the microscope and draw one cell and label it
• Eyepiece x objective lens = magnification
• Light microscope

  A) Arm

  B) Objective lenses

  C) stage

  D) Mirror

  E) Eyepiece lens

  F) Focussing Knob

  
• Image size = actual size x magnification