Day 22 M. MacLeanDay 25 M. MacLean Introduction Microscopes Introduction 1

What are microscopes used for? Microscopes “magnify” small objects or organisms. A microscope makes tiny objects viewable.

Types of microscopes Light Microscope Stereoscope 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.

Day 22 M. MacLeanDay 25 M. MacLean What are the parts of a microscope? arm stage eye piece course adjustment diaphragm stage clips objectives rotating nose piece light source base body tube fine adjustment eye piece body tube rotating nose piece arm objectives stage stage clips course adjustment diaphragm Use the worksheet. Students should fill this in as a class project. Ask the students to use the word bank to guess the names of the parts of the microscope. fine adjustment light source base 4

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