Exercise 1-2: The MicroscopeIntroduction:

The microscope is a tool used in science laboratories to view the microscopic world. These specimens include: algae, bacteria, cells, and much more. Our world is full of the creatures and are rarely seen with the naked eye. The microscope allows scientists, students, and others to view a world around us that we cannot see or rarely even notice. Without the microscope science would not be where it is today.

History:

The microscope has been around for centuries. It was invented by Van Leeuwenhoek in the 17th century. The first microscope was simple but effective and a break through during that time. The illustration below is a replica of that microscope.

Today’s microscopes have come a long way from Leeuwenhoek’s’. There are three basic types of microscopes: the compound light microscope, the transmission light microscope (TEM), and the scanning electron microscope (SEM).

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Directions: match the number with the correct word.

____ Base ____ Objective Lens ____ Head

____ Stage Clips ____ Ocular Lens

____Fine Adjustment Knob ____ Coarse Adjustment Knob

____Arm ____ Stage Adjustment

____Nose Piece ____Stage

____Light Source ____ Condensor

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1

2

7

6

54

13

3

8

910

11

12

Microscopes magnify specimens 100’s of times larger than their actual size so that they may be viewed easier and in greater detail. The ocular lens and the objective lens help in magnification. The ocular lens has a magnification power of 10x. This means that if you look through only the ocular you will see things 10 times their normal size. The objective lens has four different lenses: Scanning=4x, Low Power=10x, High Power=40x, and Oil Immersion=100x. This means that combining the ocular lens and for example the scanning lens, you will be looking at specimens 40x their natural size. This is known as the total magnification.

Directions: Complete the following chart by filling in the blanks.

Objective Lens Ocular Lens Total MagnificationScanning_____ X =Low Power_____ X =High Power_____ X =Oil Immersion_____ x =

Using the Microscope

1. Always start with the scanning (4x) objective.2. Use course adjustment and lower the stage as low as it will go.

3. Center the slide on the stage and stabilize with clips.4. Bring stage all the way up with the course adjustment.

5. Slowly lower the stage until the specimen comes into view.6. Adjust light source to increase or decrease contrast.7. Use fine adjustment to sharpen focus if necessary.

8. Move to next objective. (Low Power)9. Adjust focus if necessary.

10.Object found and focused.

11. When complete lower stage, place scanning objective in place, and turn off microscope.

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