The Microscope

Mr. Gacc/Bakka

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The History• Many people experimented with making

microscopes

• Was the microscope originally made by accident? (Most people were creating telescopes)

• The first microscope was 6 feet long!!!

• The Greeks & Romans used “lenses” to magnify objects over 1000 years ago.

The History Hans and Zacharias Janssen of Holland in the 1590’s created the “first” compound microscope

Zacharias Jansen1588-1631

The “First” Microscope

The History

• Robert Hooke & • Anton van Leeuwenhoek

made improvements by working on the lenses

Anton van Leeuwenhoek1632-1723

Robert Hooke 1635-1703

Hooke Microscope

History•In 1665 Robert Hooke examined a thin slice of cork with a single magnifying lens and observed tiny compartments

•He gave them the latin name cellulae, meaning small rooms - hence the origin of the term cell.

•He later observed cells in plant tissues and observed the cells were “fill’d with juices”

History• In the early 1700’s Leeuwenhoek

looked at pond water and called the microscopic organisms “animalcules”

• These were the first observations of living cells

• 1820 - Robert Brown observed a nucleus in orchid cells

HistoryIn 1838, Matthius Schleiden stated all plants are made of cells

Theodor Schwann stated all animals are made of cells .

Cell Theory - 3 parts

1. Cells are the basic unit of life

In 1855, Rudolf Virchow further extended the cell theory and added:

2. All organisms are composed of one or more cells

3. All cells come from pre-existing cells

How a Microscope Works

Convex Lenses arecurved glass used to make microscopes(and glasses etc.)

Convex Lenses bendlight and focus it inone spot.

How a Microscope WorksOcular Lens(Magnifies Image)

Objective Lens(Gathers light, magnifies and focuses image inside body tube)Body Tube

(Image Focuses)

•Bending Light: The objective (bottom) convex lens magnifies and focuses (bends) the image inside the body tube and the ocular convex (top) lens of a microscope magnifies it (again).

The Parts of a Microscope

Body Tube

• 1. The body tube holds the objective

lenses and the ocular lens at the proper distance

Diagram

Nose Piece

• 2. The Revolving Nose Piece holds the objective lenses and can be turned

to increase the magnification

Diagram

Ocular Lens or Eye lens

• 3. Magnifies the specimen image 10x

Diagram

Objective Lenses

• 4. The Objective Lenses increase magnification from 4x to 10x

to 40x.

Diagram

Stage Clips

• 5. These 2 clips hold the slide/specimen in place on

the stage.

Diagram

Diaphragm

• 6. The Diaphragm controls the amount of light on the slide/specimen

Turn to let more light in or tomake dimmer.

Diagram

Light Source

• 7. Projects light upwards through the diaphragm, the specimen and

the lenses

• Some have lights, others have mirrors where you must move the mirror to reflect light

Diagram

Arm

• 8. Used to support the microscope when carried. Holds the body

tube, revolving nose piece and objective lenses.

Diagram

Stage

• 9. Supports the slide/specimen

Diagram

Coarse Adjustment Knob

• 10. Moves the stage up and down (quickly) for focusing your

image.

• Never use coarse adjustment under high power!!!!!

Diagram

Fine Adjustment Knob

• 11. This knob moves the stage SLIGHTLY to sharpen the

image.

Diagram

Base

• 12. Supports the microscope

Diagram

Magnification

Magnification

• To determine your magnification…you just multiply the ocular or eye lens by the objective lens

• Ocular 10x Objective 40x:10 x 40 = 400

Objective Lens have their magnificationwritten on them.

Ocular lenses usually magnifies by 10x

So the object is 400 times “larger”

Hand lens - 5x

• Stereo microscope -

10 - 60x & 3d image

Electron Microscopecan focus up 500,000x

Tunneling - cell parts/organells

2 types of electron microscopes

Scanning - 3D image of RBCs & insects

Body Tube

Nose Piece

ObjectiveLenses

Stage Clips

Diaphragm

Light Source

Ocular Lensor eye lens

Arm

Stage

Coarse Adjustment.

Fine Adjustment

Base

Skip to Magnification Section

Using a Microscope• Start on the lowest magnification• Don’t use the coarse adjustment knob

on high magnification…you’ll break the slide!!!

• Place slide on stage and lock clips• Adjust light source (if it’s a mirror…don’t

stand in front of it!)• Use fine adjustment to focus• Use diaghram for light intensity

Caring for a Microscope

• Clean only with a soft cloth/tissue

• Make sure it’s on a flat surface

• Don’t bang it

• Carry it with 2 HANDS…one on the arm and the other on the base

Carry a Microscope Correctly

References

• http://www.cerebromente.org.br/n17/history/neurons1_i.htm• Google Images• http://science.howstuffworks.com/light-microscope1.htm