The Microscope

Slide 1: 

Instructor: Mr. Fouad Skandarani Name: Ismail Fakhro Subject: Physics ( Magnifiers ) Experiment: Microscopes Class: 10th Grade ?????? ???????? ????????

Introduction : 

Introduction In this experiment we will talk mainly about: Principle of a microscope History of microscope Parts of microscope Magnification Kinds of microscopes With some modifications how to use & carry a microscope

Microscope : 

Microscope The microscope is an instrument used to magnify very small objects . The Dutch spectacle maker : Zacharias Janssen, is credited with having discovered the principle of the compound microscope in about 1590. By 1674 Anton van Leeuwenhoek had developed microscope lenses that could magnify up to nearly 300 times. The microscope has made it possible to utilize better methods of studying biological material, particularly cells. There are two general types of microscope based on the kind of energy source used by the instrument: Light microscope Electron microscope

Old Microscopes : 

Old Microscopes

Golden Micrscope : 

Golden Micrscope

USB Microscope : 

USB Microscope

The History : 

The History Many people experimented with making microscopes Was the microscope originally made by accident? (Most people were creating telescopes) The first microscope was 6 feet long!!! The Greeks & Romans used “lenses” to magnify objects over 1000 years ago.

The History : 

The History Hans and Zacharias Janssen of Holland in the 1590’s created the “first” compound microscope Anthony van Leeuwenhoek and Robert Hooke made improvements by working on the lenses Anthony van Leeuwenhoek 1632-1723 Robert Hooke 1635-1703 Hooke Microscope

The History : 

The History Zacharias Jansen 1588-1631 The “First” Microscope

How a Microscope Works : 

How a Microscope Works Convex Lenses are curved glass used to make microscopes (and glasses etc.) Convex Lenses bend light and focus it in one spot.

How a Microscope Works : 

How a Microscope Works Ocular Lens (Magnifies Image) Objective Lens (Gathers Light, Magnifies And Focuses Image Inside Body Tube) Body Tube (Image Focuses) Bending Light: The objective (bottom) convex lens magnifies and focuses (bends) the image inside the body tube and the ocular convex (top) lens of a microscope magnifies it (again).

The Parts of a Microscope : 

The Parts of a Microscope

Slide 15: 

Body Tube Nose Piece Objective Lenses Stage Clips Diaphragm Light Source Ocular Lens Arm Stage Coarse Adj. Fine Adjustment Base Skip to Magnification Section

Body Tube : 

Body Tube The body tube holds the objective lenses and the ocular lens at the proper distance Diagram

Nose Piece : 

Nose Piece The Nose Piece holds the objective lenses and can be turned to increase the magnification Diagram

Objective Lenses : 

Objective Lenses The Objective Lenses increase magnification (usually from 10x to 40x) Diagram

Stage Clips : 

Stage Clips These 2 clips hold the slide/specimen in place on the stage. Diagram

Diaphragm : 

Diaphragm The Diaphragm controls the amount of light on the slide/specimen Turn to let more light in or to make dimmer. Diagram

Light Source : 

Light Source Projects light upwards through the diaphragm, the specimen and the lenses Some have lights, others have mirrors where you must move the mirror to reflect light Diagram

Ocular Lens/Eyepiece : 

Ocular Lens/Eyepiece Magnifies the specimen image and is always 10x. Diagram

Arm : 

Arm Used to support the microscope when carried. Holds the body tube, nose piece and objective lenses Diagram

Stage : 

Stage Supports the slide/specimen Diagram

Coarse Adjustment Knob : 

Coarse Adjustment Knob Moves the stage up and down (quickly) for focusing your image Diagram

Fine Adjustment Knob : 

Fine Adjustment Knob This knob moves the stage SLIGHTLY to sharpen the image Diagram

Base : 

Base Supports the microscope Diagram

Magnification : 

Magnification

Magnification : 

Magnification To determine your magnification…you just multiply the ocular lens by the objective lens Total magnification= Ocular (10x) x objective (4,10,40,100) Objective Lens have their magnification written on them.

Slide 30: 

ocular stays the same 10x and objective change. Objectives rotate in nosepiece Changing objectives changes total magnification

Low power objective (10X) : 

Low power objective (10X) Total magnification = 10(ocular) X 10(objective)

High power or high dry objective : 

High power or high dry objective Total magnification = 10(ocular) X 40(objective)

Kinds Of Microscopes : 

Kinds Of Microscopes light Simple Compound Stereoscopic Electron

Simple Microscope : 

Simple Microscope Similar to a magnifying glass and has only one lense. The light passes through glass lense resulting in a magnified Image seen by the eye.

The Compound Light Microscope : 

The Compound Light Microscope Is the most frequent one has two magnifying lenses uses light for viewing most commonly used scope Ocular lense Objective lense

Stereoscopic Microscope : 

Stereoscopic Microscope Gives a three dimensional view of an object. (Examples: insects and leaves). Has the same structure (basically) as the compound microscope. Has much greater field of view and depth of field than the compound microscope. Not designed for greater magnification where the maximum magnification in it is about 30x.

Electron Microscope : 

Electron Microscope Electron microscope do not function by light, it operate by a stream of electron Originating from an electron source within the instrument. Electron stream is focused by magnetic lenses resulting In a magnified image appearing on photographic film or on a fluorescent Screen similar to a television picture tube. They are costly and large in size, electron microscope is very dangerous for living organisms.

Slide 38: 

There are 2 basic types of electron microscope : The scanning electron microscope: scans the specimen with a spray of electrons and image by detecting electrons coming back from the specimen. The transmission electron microscope: works in a manner similar to the compound microscope, the specimen must be thinly sectioned which allows electrons to pass through it. The electrons through the specimen are scattered in pattern similar to the specimen structure.

Slide 40: 

What are Electron Microscopes? Electron Microscopes are scientific instruments that use a beam of highly energetic electrons to examine objects on a very fine scale. This examination can yield the following information: Topography The surface features of an object or "how it looks", its texture; direct relation between these features and materials properties (hardness, reflectivity...etc.) Morphology The shape and size of the particles making up the object; direct relation between these structures and materials properties (ductility, strength, reactivity...etc.) Composition The elements and compounds that the object is composed of and the relative amounts of them; direct relationship between composition and materials properties (melting point, reactivity, hardness...etc.) Crystallographic Information How the atoms are arranged in the object; direct relation between these arrangements and materials properties (conductivity, electrical properties, strength...etc.)

Pictures Taken By an Electron Microscope : 

Pictures Taken By an Electron Microscope 350x

Slide 42: 

Spaider leaf vain: 350x

Mosquito’s Head : 

Mosquito’s Head 250x 1000x

Toilet Paper : 

Toilet Paper 500x

Using a Microscope : 

Using a Microscope Start on the lowest magnification Don’t use the coarse adjustment knob on high magnification…you’ll break the slide!!! Place slide on stage and lock clips Adjust light source (if it’s a mirror…don’t stand in front of it!) Use fine adjustment to focus

Caring for a Microscope : 

Caring for a Microscope Clean only with a soft cloth/tissue Make sure it’s on a flat surface Don’t bang it Carry it with 2 HANDS…one on the arm and the other on the base

Carry a Microscope Correctly : 

Carry a Microscope Correctly

References : 

References http://www.cerebromente.org.br/n17/history/neurons1_i.htm Google Images http://science.howstuffworks.com/light-microscope1.htm Biology 150 ( Lab Manual ).