Microscopes

Introduction

What are microscopes used for?

• Microscopes “magnify” small objects or organisms.

• A microscope makes tiny objects viewable.

Types of microscopes• Light Microscope

– Used for viewing living organisms.– The lenses bend or refract the light, which makes the object beneath them

appear closer

• Stereoscope– This microscope allows for binocular (two eyes) viewing of larger specimens

• Scanning Electron Microscope– Allows scientists to see things that are too small for a light microscope.– This type of microscope uses electrons to magnify objects up to a million

times.

• Transmission Electron Microscope– This microscope also uses electrons but in this case they pass through a

specimen.

What are the parts of a microscope?arm stage eye piece course adjustmentdiaphragm stage clips objectives rotating nose piecelight source base body tube fine adjustment

eye piece

arm

stage

course adjustment

fine adjustment

base

light source

diaphragm

stage clips

objectives

rotating nose piece

body tube

How do you focus a microscope?• Always start with the scanning objective.

• Use the Course Knob to focus.

• Do not use the stage clips or move the slide to focus.

• Switch to Low Power and use the Course knob to refocus. (Do not use the High Power if you cannot get the specimen or slide into focus.)

• Switch to high power and use the Fine Adjustment Knob to focus.

How do I see the specimen?

• Step 1: Place a small sample on the slide.• Step 2: Put 1 drop of water on specimen• Step 3: Hold slip cover at a 45 degree angle.• Step 4: Drop the slip cover.• Step 5: Change microscope to the scanning

objective.• Step 6: Mount the slide.• Step 7: Focus using the course knob.• Step 8: Record what you see.

How do you create a “wet mount”?

• Step 1: Place a tiny piece of the specimen onto the slide.

• Step 2: Place 1 drop of water onto the specimen.

• Step 3: Hold slip cover at a 45 degree angle over the wet specimen.

• Step 4: Let the slip cover fall onto the wet specimen.

Are you ready to use a microscope?

Web-Resources

• Biology Corner: http://www.biologycorner.com/bio1/microscope.html

• Images Microsoft Office: http://office.microsoft.com/en-us/images/

• Power Point: M. MacLean, ESUHSD