Transcript 3.16 Microscopes

March 16th Part III
• Microscope Notes,Video
• Lab 12: Microscope & Cells
• Exam II on 3.30 (Lectures
5,6,7,8,9,10) and Microscopes
• Bring Lab 11
• HW Handouts
– Membrane Structure
– Cell Transport
– Cell Respiration
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The 50 Cent Microscope !!!
2
Microscope Notes
Microscopes
• Objectives
– Identify different parts of a compound light
microscope
– Understand how magnification of an object
is calculated
– Use a microscope to observe objects at
different magnifications
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Microscope
One or more lenses that makes an enlarged image of an
object.
Early Microscopes
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Types of Microscopes
•
•
•
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Simple
Compound
Stereoscopic
Electron
Simple Microscope
• Similar to a magnifying glass and has only
one lens.
Compound Microscope
• Lets light pass through an object and then
through two or more lenses.
Stereoscopic Microscope
• Gives a three dimensional view of an
object. (Examples: insects and leaves)
Electron Microscope
• Uses a magnetic field to bend beams of electrons;
instead of using lenses to bend beams of light.
Electron
Microscope Images
A Lense
• Enlarges an image and bends the light
toward your eye.
Eyepiece Lense
Usually has a power of 10 x
Total Magnification
Eyepiece Lens
X
Objective Lens
=
Total Magnification
Objective Lenses
Low Power = 4 x
Medium Power = 10 x
High Power = 40 x
"Leeuwenhoek was a man with many talents,
his most important attributes were creativity,
power of observation, and ingenuity.
Microscope Rules
• Always use both hands to carry microscope;
one hand holds the arm, the other hand is
under the base
• Always start looking at your sample with
lowest power objective
• Focus first with coarse adjustment knob,
then sharpen image with fine adjustment
• After image is in focus at lowest power,
rotate nose piece to next higher objective
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lens; use fine adjusment to refocus
Lab 12: Microscope & Cell
• Exercise I: Calculating Total
Magnification
• Exercise 2: Inversion
• Exercise 3: Field of View
• Exercise 4: Depth of Field
• Exercise 5: Cheek Cell Wet Mount
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