Introduction to the

Microscope

▪Care▪Parts▪Focusing

Quick Write:

1. What is the function of a microscope?2. How do you calculate for the power of

magnification of a microscope?

STUDENTS WILL:

• Know the parts of the microscope• Know the function of each parts of the

microscope.• Know how to use and care for the

microscope• Discuss the history of the microscope• Identify the types of microscope

VOCABULARY

• EYEPIECE• NOSEPIECE• OBJECTIVE LENSES• STAGE CLIPS• COURSE ADJUSTMENT KNOB• FINE ADJUSTMENT KNOB• DIAPRAGHM• Resolution • Magnification

• Always carry with 2 hands• Only use lens paper for cleaning• Do not force knobs• Always store covered• Keep objects clear of desk and cords

• Place the Slide on the Microscope

• Use Stage Clips • Click Nosepiece to the

lowest (shortest) setting

• Look into the Eyepiece• Use the Coarse Focus

• Follow steps to focus using low power• Click the nosepiece to the longest

objective• Do NOT use the Coarse Focusing Knob• Use the Fine Focus Knob to bring the

slide

What can you find on your slide?

What’s my power?

To calculate the power of magnification, multiply the power of the ocular lens by the power of the objective.

Comparing Powers of

Magnification

• We can see better details with higher the powers of magnification, but we cannot see as much of the image.

• Which of these images would be viewed at a higher power of magnification?

Eyepiece

Body Tube

Revolving NosepieceArm

Objective Lens

StageStage Clips

Coarse Focus

Fine Focus

Base

Diaphragm

Light

TERMS TO KNOW…

1. ARM- used to support the microscope when it is carried.

2. COURSE ADJUSTMENT KNOB-

moves the stage up and down for focusing.

3. FINE ADJUSTMENT KNOB-

moves the stage slightly sharpen the image.

4. DIAPHRAGM- regulates the amount of light on the specimen.

5. BASE- supports the microscope

6.EYEPIECE- allows you to view the image on the stage and contains the ocular lens.

7. NOSEPIECE- holds the HIGH –and LOW- power objective lenses; can be rotated to change magnification.

8. OBJECTIVE LENSES- found on the nose piece and and range from low to high power. (10x to 40x)

9. STAGE CLIPS- hold the slide in place

10. LIGHT SOURCE- projects light upwards through the diaphragm, the specimen, and the lenses.

11.STAGE- supports the slide being viewed.

12. Body Tube – holds and support the eyepiece

History of the Microscope

•1590 –First compound microscope

• 1590 -Zaccharias and Hans Janssen experimented with lenses in a tube, leading to the forerunner of the microscope and the telescope

•1655 – Robert Hooke used a compound microscope to observe pores in cork

–He called them “cells”

•Antoine van Leeuwenhoek –1st to see single-celled organisms in pond water

•Magnification: increase of an object’s apparent size.

•Resolution: power to show details clearly

• Simple• Compound• Electron

Simple Microscope

1. Similar to a magnifying glass and has only one lense.

2. Compound Light

Microscope

–1st type of microscope, most widely used

–light passes through 2 lenses–Can magnify up to 2000x

Ocular lens

Objective lenses

3. Electron Microscope

–Used to observe VERY small objects: viruses, DNA, parts of cells

–Uses beams of electrons rather than light

–Much more powerful–2 Types

A. Transmission Electron

Microscope (TEM)

-Can magnify up to 250,000x

B. Scanning Electron

Microscope (SEM)

-Can magnify up to 100,000x