Transcript the microscope

The Microscope
Learning Objectives
By the end of this topic, you will be able to:
1. Name the parts of the microscope and
their functions.
2. Use the microscope to observe biological
specimens
3. Know the difference between the light
microscope and the electron microscope
Compound Microscopes
The microscopes used in our lab are called
compound microscopes because they have
two magnifying lens
a.
The Eyepiece Lens is the
lens that you look through.
b.
The objective lens is the
lens that is immediately above
the specimen.
The Objective Lenses
There are three objective lenses:
- the scanning lens with the 4X label
- the low power lens with the 10X label
- the high power lens with the 40X label
Parts of the Microscope
Parts of the Microscope
Part
Function
Lenses
Magnification
Stage
To place the slide on
Clips
Hold the slide in place
Diaphragm
To control the amount of light
Coarse Focus Knob
To focus the image
Fine Focus Knob
To precisely focus the image
Light
To supply light to the object
Learning Check
Label the parts of the Microscope
Magnification
Magnification =
the magnifying power of the eyepiece lens
x
the magnifying power of the objective lens.
Example:
Eyepiece lens = 10X
Objective lens = 4X
Total magnification = 10 x 4= 40X
Focussing The Image
The course focus knob allows for
dramatic or large movement of the
objective lens.
The fine focus knob allows for very
slight movement of the objective
lens.
The Stage and the Diaphragm
The stage has two metal clips to hold
the microscope slide in place.
The diaphragm allows light to be
focused onto the specimen through a
hole in the stage.
ELECTRON MICROSCOPE
Electron Microscope


Uses Electrons instead of light
Electrons have much lower wavelength
than light

Resolution is much better

Magnification is much greater
Images from Electron
Microscope
Bacteria
Platelet
Cytplasm
Learning Check
What is the function of each of
these parts of the Microscope?
Eyepiece Lens
Stage
Diaphragm
Fine focus Knob
Objective Lens
Clips
Coarse Focus Knob
Light
What have you learned?
Can you?
1. Name the parts of the microscope and
their functions.
2. Use the microscope to observe biological
specimens
3. Outline the differences between the
light microscope and the electron
microscope