1. Notes: Microscopes
Microscope
A tool used to produce magnified images of an object or an organism
The microscope that is used depends on what details you want to reveal.
Below is an example of a protist seen using three different kinds of microscopes (at the same magnification).

2. Types of Microscopes Compound Light Microscope:
Uses two lenses: ocular lens (or eyepiece) and objective lens
Used to magnify and show detail of a translucent specimen (one that light can pass through).
Image is inverted (meaning upside down and backwards) as a result of the lenses that are used.
Can magnify up to times (The ones we have only magnify up to 400 times).

3. Magnification
The equation below is used to calculate total magnification:
Total magnification = magnification of the ocular lens X magnification of objective lens
Ex: If the eyepiece magnifies the image 10x and the low power objective magnifies the image 10x, then the total magnification of the image would be:
10x x 10x = 100x

4. Total Magnification= Eyepiece x Objective Lens

5. Compound light microscopes continued
Two types of slide will be used in our class:
Prepared slides – professionally made slides with a permanent cover slip over the specimen.
Wet mounts - temporary slides that you prepare yourself.

6. The greater the magnification, the smaller the field of view will be.
Field of View– This is the visible area seen through the microscope when the specimen is in focus.
The greater the magnification, the smaller the field of view will be.
Low Power
Medium Power
High Power

7. Stereomicroscope (also known as Dissecting Microscope).
Useful when viewing objects that are too large or too thick for the compound light microscope.
Unlike the compound light microscope, the images seen are not inverted. This is because you are using two eyepieces (binocular scope).
Can only magnify up to 4 – 50 times.

8. Scanning Electron Microscopes – SEM*
Specimen is coated with a thin layer of metal.
Electrons are scanned back and forth over an object
Shows the surface only
Show the object in 3 dimensions (3-D)…in other words, you can see depth.
Can magnify up to 100,000 times

9. Transmission Electron Microscope – TEM*
Electrons are beamed or “shot” at an object and then shown on a screen
A thin cross section of the specimen must be made.
Electrons pass through the object - allows you to “see” inside
2 dimensional view (2-D)
Can magnify up to 200,000 times

10. ** A big problem of the SEM and TEM is that the specimen must be dead in order to view in with one of these microscopes.
Go to the site below to practice with a virtual microscope!