Created by J. Cook
The Compound Microscope
The Compound Microscope
Preparing a wet mount slide
What are the steps?
1.Place one or two drops on slide.
2.Cover with slip at 45○ angle.
3.Gently press down to remove air bubbles.
Sketches
List the 6 components of a sketch.
1.Name the object
2.Write the total magnification.
3.Complete a detailed sketch. Use pencil.
4.Label important parts.
5.Show the measurement (size of object).
6.Make detailed written observations of
things that can’t be shown in sketch:
descriptions of movement/behavior etc. .
What is the benefit of each power?
LOW:
Scanning. Finding objects. Viewing a large
area of the slide.
MEDIUM: Greater detail than low, but can still see a
fairly large area of slide. Easier to follow moving
organisms than on high power.
HIGH: Greatest magnification to see the most
detail.
Using High Power
1. Get object in sharp focus on low, then medium
power before going to high.
2. The object must be centered.
3. Once on high power only small adjustments
should be needed.Use only the fine adjustment
knob.
4. Often requires more light than low or medium
power.
5. Objects at slightly different levels will not all be
in focus at the same time.
6. If you “lose” an object on high power you will
have to go back to medium or low to find it again.
Trouble Shooting
How do you focus an object?
1.Always start on low power
2.Use Coarse adjustment first.
3.Then use fine adjustment
What if no light is coming through?
1.Turn on the microscope and all power strips.
2.Adjust the diaphragm
3.Clean the lenses
4.Make sure the nose piece is “clicked” into place.
Actual Field Diameters of Our Microscopes
Write these numbers down in a safe place. You will need
to know them all year long!
POWER
MAGNIFICATION
FIELD
DIAMETER
Low
40X
100X
4500 µm
1800 µm
400X
450 µm
Medium
High
Measuring under a microscope
How is total magnification calculated?
The objective lens multiplied by the eye piece
What is the “field diameter”?
The distance across the lighted circle you see when
looking through the microscope.
What is the general formula used to
determine the size of an object?
The field diameter divided by how many of that object
you estimate would fit across the diameter.
The Dissecting Microscope
Comparing and Contrasting
the microscopes
 List some similarities for both microscopes.
 State some differences for the Compound
microscope.
 State some differences for the Dissecting
microscope.
(Include purpose, type of object to view,
appearance of objects etc.)