The Microscope

The Microscope

Learning ObjectivesBy 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

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 microscopes used in our lab are called compound microscopes because they have two magnifying lens

The Objective LensesThere 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 MicroscopePart Function

Lenses MagnificationStage To place the slide onClips Hold the slide in placeDiaphragm To control the amount of

lightCoarse Focus Knob

To focus the image

Fine Focus Knob To precisely focus the imageLight To supply light to the object

Learning CheckLabel the parts of the

Microscope

MagnificationMagnification = the magnifying power of the eyepiece lens

x the magnifying power of the objective lens.

Example:

Eyepiece lens = 10XObjective lens = 4X

Total magnification = 10 x 4= 40X

Focussing The ImageThe 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

Cytplasm

Platelet

Learning CheckWhat is the function of each of these parts of the Microscope?

Eyepiece Lens Objective LensStage ClipsDiaphragm Coarse Focus KnobFine 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

END