microscope from Greek: micro- “small” -scope “instrument for viewing” A microscope is an instrument used to view objects that are too small to be easily seen with just our eyes.
We use microscopes to see more detail in things we can see everyday sand Sand under a microscope
Or tree Tree under a microscope
Or to look at things we can’t see at all Household dust Bread mold Fly eye Cancer cell Cat flea
History Dutch spectacle- maker (eye glasses ), Zacharias Janssen, o experimented with multiple lenses placed in a tube o Viewed objects in front the tube appeared BIGGER!!! This led to the creation of the first compound microscope & the telescope “LENS” from the Latin word “LENTIL”
1665 Robert Hooke, an English scientist, improved the original microscope design He then saw little empty boxes that reminded him of prison cells He called what he saw “cells”. CELL: Basic building block of all animal & plant life
1673 Anton Van Leeuwenhoek, “father of microscopy” Made a simple microscope with only one lens….it was able to magnify up to 270X First scientist to describe bacteria Studied blood, yeast, insects and other tiny objects Blood cells Yeast Cells Dust mites looking for human skin on a bed sheet
Compound Light Microscope Magnifies like binoculars Light passes through both the lenses and the object you are looking through.
What’s My Power? Power of the xPower of the EyepieceObjective Lens =EQUALS= TOTAL power of magnification Example: 10 x 4 = 40x
What’s My Power? Eyepiece o This lens magnifies 10X Objective Lenses There are 3 different objective lenses Low power 4X (red) o Total magnification: 10X times 4X = 40X larger Medium power 10X (yellow) o Total magnification: 10X times 10X = 100X larger High power 40X (blue) o Total magnification: 10X times 40X = 400X larger
Comparing Powers of Magnification We can see better details with higher the powers of magnification, but we cannot see as much of the image
Parts of the Microscope Eyepiece – concentrates light on what you are looking at and provides a viewing place Body tube – holds focusing adjustment knobs and objective lenses Objective lenses – principle magnifiers (low, medium, high) Stage – supports the slide or specimen Stage clips (TWO) – holds the slide or specimen in place
Light source – provides light for viewing Arm – supports body tube and a place to transport the microscope Base – provides stability and supports the microscope Diaphragm – controls the amount of light coming through the stage Specimen – the object to be viewed under the microscope
Coarse adjustment knob – moves the stage up and down to allow focusing of the image Fine adjustment knob – moves the stage slightly to bring the image into sharper focus Revolving nosepiece – holds the objective lenses and turns to allow the desired objective lens to click into place Field of view – circle of light that comes through the stage
Care of the Microscope CARRY with TWO hands – one on the arm & the other on the base NEVER touch the lenses with your bare hands – oils from your hands can smear the glass and led to scratches WHEN YOU ARE DONE, CLEAN UP! o Unplug o Wrap the cord around the bottom of the arm o Clean your slides and table o Return all materials where they were found o AKA – U.W.C.R. )Ursula Will Cause Riots BE CAREFUL with slides & coverslips as they break easily
Let’s give it a try! 1. Unwrap the cord and plug into the closet outlet 2. Turn on the microscope 3. Rotate the microscope towards you – NOT THE EYEPIECE 4. Rotate the nosepiece to clock the red-banded (4x) objective into place 5. Place a slide on the stage & secure it using BOTH the stage clips 6. Use the COARSE adjustment knob (large knob) to get the image into view & focused. You should see the stage should move up & down 7. Now use the FINE adjustment knob (small knob) to make the image sharper 8. Once you have the image in view, rotate the nosepiece to view it under different powers BE CAREFUL WITH THE LARGEST OBJECTIVE LENS! SOMETIMES THERE IS NOT ENOUGH ROOM & YOU WILL NOT BE ABLE TO USE IT!! 9. When you are done…..U.W.C.R.!!!