Microscope Basics

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Microscope
Basics
T. Trimpe 2005 http//sciencespot.net/
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MICROSCOPES

• MAGNIFIES OBJECTS (MAKES OBJECTS LOOK BIGGER)
• HELP SCIENTISTS STUDY OBJECTS LIVING THINGS TOO
  SMALL TO SEE WITH THE NAKED EYE

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Ocular lens(Eyepiece)
Body Tube
Nosepiece
Arm
Objectives
Stage
Stage Clips
Coarse Adjustment
Fine Adjustment
Light
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3 Types of Microscopes

• simple microscope has only 1 lens. compound
  microscope has 2 sets of lenses. It can magnify
  things 100 - 200 times larger than they really
  are.
• electron microscope can magnify objects up to
  300,000 times. They do not use lenses, but use
  electrons to enlarge the image.

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PARTS OF A MICROSCOPE

• ocular (lens) eyepiece
• the lens of the microscope that you look through
• course adjustment
• the large knob on the microscope that you turn to
  bring the object into focus
• fine adjustment
• the small knob on the microscope that brings the
  image into focus

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PARTS OF A MICROSCOPE

• arm
• the part of the microscope supporting the body
  tube
• body tube
• the part that holds the eyepiece and the
  objective lenses.
• nosepiece
• the part at the bottom of the body tube that
  holds the objective lenses and allows them to be
  turned

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• high power objective lens
• the lens that magnifies the object the greatest
  amount. (usually 40x)
• Low power (scanner) objective lens
• the lens that magnifies the object the least
  amount (usually used to find the object
  magnifies only 3x or 4x)
• middle power objective lens
• the lens that usually magnifies the object more
  than the scanner lens, but less than the high
  power lens (usually 10x to 20x)

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• 10. stage
• the flat part below the objectives lens where the
  slide is placed
• 11. clip
• the part that holds the slide in place so it
  doesnt move
• 12. diaphragm
• the part that controls the amount of light
  entering the field of view

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• 13. light source
• the lamp (or mirror) under the stage that sends
  light through the object being viewed.
• 14. base
• the bottom part that supports the rest of the
  microscope

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Ocular lens(Eyepiece)
Body Tube
Nosepiece
Arm
Objectives
Stage
Stage Clips
Coarse Adjustment
Fine Adjustment
Light
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Field of View

• Field of view is the area (circle) that you see
  when looking through the eyepiece

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Comparing Powers of Magnification
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Whats my power? To calculate the power of
magnification, multiply the power of the ocular
lens by the power of the objective.
What are the powers of magnification for each of
the objectives we have on our microscopes? Fill
in the table on your worksheet.
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Calculating Magnification

• 1. Find the power of the lens. It is found on
  the side of the lens. Magnification power of a
  lens is always identified by the label of x (10x,
  1000x)
• 2. Multiply the power of the eyepiece by the
  power of the objective lens.
• 3. Examples
• eyepiece obj. lens
• 10x times 100x
• 10x times 50x
• 10x times 40x

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Appearance of the Specimen

• Objects appear upside-down backward
• Movement appears to be in opposite direction than
  actual movement 1 2
• move slide
• slide appears to move
• 2 1

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Lets give it a try ...
1 Turn on the microscope and then rotate the
nosepiece to click the red-banded objective into
place.
2 Place a slide on the stage and secure it
using the stage clips. Use the coarse adjustment
knob (large knob) to get it the image into view
and then use the fine adjustment knob (small
knob) to make it clearer.
4 When you are done, turn off the microscope
and put up the slides you used.
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Recording Observations

• Draw specimen large enough to fill field of
  view circle
• Draw as many details as possible
• Drawing should be neat
• Label specimen
• Label power of magnification
• Name date on paper

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Making a Wet Mount Slide

• 1. Use dropper to place a drop of water on the
  center of a clean slide.
• 2. Use tweezers to lay specimen on the drop of
  water.
• 3. Gently touch the cover slip to the edge of
  the drop of water to cover the specimen the
  water.

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How to make a wet-mount slide 1 Get a clean
slide and coverslip from your teacher. 2 Place
ONE drop of water in the middle of the slide.
Dont use too much or the water will run off the
edge and make a mess! 3 Place the edge of the
cover slip on one side of the water drop.