magnificationmagnification copyright © 2010 ryan p. murphy

magnification

Copyright © 2010 Ryan P. Murphy

The act of expanding something in apparent size


• Magnification: The act of expanding something in apparent size.– The object doesn’t change in size.

DE-MAGNIFICATION To make something smaller in

appearance


How is magnification useful?


Copyright © 2010 Ryan P. MurphyCopyright © 2010 Ryan P. Murphy

Magnifying glass


Eye glasses

To see very small things


Surgical and medical applications


Crime investigation– Two different bullets shot from the same

gun shown below.


Which of the bills below is counterfeit?


Military use


• Space exploration (telescope)


• The Movies


• Cameras and recording devices.


Magnification works because of light. Without light, you would not be able to

see any image, magnified or not


• Activity! Hand Lens– Use a hand lens to practice focusing on a US $1

dollar bill. Record two pictures of neat things that you find.

– Try and find the hidden owl.


• Picture of microprint on 20$ Bill.


Convex lens: A convex lens bends the light that goes through it toward a focal point. The light spreads out again past this focal point.

e e


Convex lens: Image is reversed

e e


http://www.shokabo.co.jp/sp_e/optical/labo/lens/lens-a2.gif

Although magnification is possible with only one lens, it also can be achieved by using

more than one.


Magnifying lens uses a single lens to magnify the specimen. Focusing can occur by

moving the object or your eye.


Which microscope should be used to view a bumble bee, living cell, and deep into a

dead cell?


Which device should we use to look at the specimen on the

left?


The device in the middle, called a stereoscope is used

for large objects?


Which device should we use to look at the specimen on the

left?


The microscope on the right is a compound light microscope and is used for very small specimens that light can

pass through.


• It looks at things in which light cannot pass through (e.g. a bumble bee)

• Lets you see the image in 3D

Copyright © 2010 Ryan P. MurphyCopyright © 2010 Ryan P. Murphy

STEREOSCOPIC MICROSCOPE

It lets you magnify images that light can pass through.

Uses a glass slide and cover slip.


LIGHT COMPOUND MICROSCOPE

You do not put large objects under a light microscope such a rock, pencil, finger, etc. !

Specimens need to be incredibly thin and light must pass through. Uses Slides!


It can magnify specimens much smaller than a light, or stereoscope

It doesn’t usually view live cells or specimens


ELECTRON MICROSCOPE

Scanning Electron Microscope


SEM


TEM Transmission Electron Microscope


http://www.mos.org/sln/SEM/mascara.gif


http://www.mos.org/sln/SEM/clamgill.gif


http://www.mos.org/sln/SEM/tpaper.gif


http://electronmicroscope.files.wordpress.com/2008/11/guitar-stringtif1.jpg


http://www.photosfan.com/images/electron-microscope-pictures-microorganism1.jpg

http://www.photosfan.com/images/electron-micrograph-picture-scales-or-armour.jpg

Head of a flea



Stapled paper


Mascara brush

http://www.mos.org/sln/SEM/mascara.gif


Diatom (Protista) Shell made of glass.


Cross section of a leaf.


Clam Gills

http://www.mos.org/sln/SEM/clamgill.gif

Eye of a fruit fly.


Variety of Pollen Grains.


Human hair.


Toilet Paper

http://www.mos.org/sln/SEM/tpaper.gif


Electric Guitar String

http://electronmicroscope.files.wordpress.com/2008/11/guitar-stringtif1.jpg


Avian Flu Virus


Nylon stockings


Microorganisms on a sheet of paper.

http://www.photosfan.com/images/electron-microscope-pictures-microorganism1.jpg

Aquatic skin parasites on fish.

Reptile Scales

http://www.photosfan.com/images/electron-micrograph-picture-scales-or-armour.jpg


Microscopic Spider


Dust mite. If you are allergic to dust, it is most likely the feces of the dust mite.

Porcupine quill

Claw of Black Widow Spider


An atomic force microscope lets you see all the way to the atom.

When carrying a microscope, carry it by the arm, and have one hand under the base.



Watch out for cords that hang off of the table waiting to be stepped on and pulling the microscope to the ground.Wrap the cord around arm for storage.

• Always lower the stage after use so the gears are not strained.

– Remove any slide as well.– The finely tuned gears are what make

microscopes expensive.


Remember dust cover for proper storage.


The eyepiece lens is 10x – That means it magnifies the object ten times

Low power is usually 4x Medium power is usually 10x High power is usually 40x


How many times larger is an image magnified under low power.

Eye Piece x Low Power Lens =



Eye Piece x Low Power Lens = 10 x 4 =



Eye Piece x Low Power Lens = 10 x 4 = 40 magnification


How many times larger is an image magnified under medium power and high

power.Eye Piece x Medium Power Lens = 100

times magnification


How many times larger is an image magnified under medium power and high

power.Eye Piece x High Power Lens = 400 times

magnification


Create three circles using a Petri-dish.Label the circles, low, medium and high power


To focus the microscope… place the slide under the stage clips and

adjust the diaphragm so light passes through.

oTurn revolving nose piece to the low power lens.

High Power



To focus the microscope… With the low power lens, gently turn the coarse focus until the image comes

into focus.oOnce in focus, you can now use the revolving

nosepiece to move the medium power lens into position.


With the medium power lens, gently turn the coarse adjustment until the image comes into focus.

oOnce in focus, you can now use the revolving nosepiece to move the high power lens into position.


With the high power lens, gently turn the fine adjustment until the image comes into focus.

Do not use the coarse adjustment when the microscope is using the high power

lens. This can break the glass slide and damage

the microscope.

Using the microscope1. Please place the letter e on a slide and put a cover

slip on.2. Sketch the letter e on low, medium, and high power.


Practice your skills with prepared slides.


Pull out a hair and put it under the microscope with a

cover slip. Sketch your image.


• Activity! Using a depressed slide.– Add one drop of pond water to the depression in

the slide, add a cover slip.


magnificationmagnification copyright © 2010 ryan p. murphy

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