Download Preparing an Onion Cell Slide

Preparing an Onion Cell Slide
.
An onion is made of lots of concentric layers. Each layer is
separated by a thin skin or membrane. In this experiment you will
make a slide and look at the cells of the membrane under a
microscope.
Membrane
Method
1) Take a small piece of onion and using forceps (tweezers)
peel off the membrane from the underside (the rough side).
2) Lay the membrane flat on the surface of a clean glass slide
then add 1 drop of stain (iodine or methylene blue). Be
very careful, these dyes will stain your skin and clothes.
Iodine
3) Using a pin. Lower a thin glass cover slip over the slide.
Make sure there are no air bubbles.
4) Put the slide onto the stage of the microscope. Make sure
the objective lens is set on low power, and the microscope
light is turned on.
Eyepiece lens
Objective
lens
Stage
5) Look through the eyepiece lens and turn the focusing wheel
until you can see the cells.
6) Draw what you can see in your jotter. Label any parts of the plant
cell that you could identify.
Light source
Rough and fine
focussing
wheels