The document provides a history of the microscope from its early origins as a simple magnifying glass to its modern compound forms. Key developments include the earliest compound microscopes created by the Janssens in 1590 using multiple lenses, Anton van Leeuwenhoek's simple single-lens microscope in 1674 that allowed him to be the first to observe bacteria, and later innovations such as phase-contrast microscopy, electron microscopy, and scanning tunneling microscopy that enabled viewing objects much smaller than the wavelength of light. The document also describes the basic parts and functions of the modern compound microscope, including its tube, lenses, stage, light source, and other components.

1. SECOND GRADING
TOPIC 2b:
The MICROSCOPE

2. Getting to
know
The microscope

3. What is a microscope for?
An instrument for viewing objects
that are too small to be seen
easily by the naked eye.

4. HISTORY:
 Circa 1000AD – The first vision aid was
invented (inventor unknown) called a reading
stone. It was a glass sphere that magnified
when laid on top of reading materials.
 Circa 1284 - Italian, Salvino D'Armate is
credited with inventing the first wearable eye
glasses.

5. THE READING STONE & FIRST EYE GLASSES

6.  1590
Two Dutch eye glass makers, Zaccharias
Janssenand son Hans Janssen experimented
with multiple lenses placed in a tube. The
Janssens observed that viewed objects in front
of the tube appeared greatly enlarged,
creating both the forerunner of the compound
microscope and thetelescope.

7. Microscopes by Janssen
Zaccharias
Janssen

8.  1665 – English physicist, Robert Hooke looked at a
sliver of cork through a microscope lens and
noticed some "pores" or "cells" in it.
 1674 – Anton van Leeuwenhoek built a simple
microscope with only one lens to examine blood,
yeast, insects and many other tiny objects.
Leeuwenhoek was the first person to describe
bacteria, and he invented new methods for
grinding and polishing microscope lenses that
allowed for curvatures providing magnifications of
up to 270 diameters, the best available lenses at
that time.

10.  18th century – Technical innovations improved
microscopes, leading to microscopy becoming
popular among scientists. Lenses combining two
types of glass reduced the "chromatic effect" the
disturbing halos resulting from differences in
refraction of light.
 1830 – Joseph Jackson Lister reduces spherical
aberration or the "chromatic effect" by showing that
several weak lenses used together at certain
distances gave good magnification without blurring
the image. This was the prototype for the compound
microscope.

12.  1872 – Ernst Abbe, then research director of the
Zeiss Optical Works, wrote a mathematical formula
called the "Abbe Sine Condition". His formula
provided calculations that allowed for the
maximum resolution in microscopes possible.
 1903 – Richard Zsigmondy developed the
ultramicroscope that could study objects
below the wavelength of light. He won the
Nobel Prize in Chemistry in 1925.

13. Ultramicroscope

14.  1932 – Frits Zernike invented the phase-contrast
microscope that allowed for the study of colorless and
transparent biological materials for which he won the
Nobel Prize in Physics in 1953.
 1931 – Ernst Ruska co-invented the electron
microscope for which he won the Nobel Prize in Physics
in 1986. An electron microscope depends on electrons
rather than light to view an object, electrons are
speeded up in a vacuum until their wavelength is
extremely short, only one hundred-thousandth that of
white light. Electron microscopes make it possible to
view objects as small as the diameter of an atom.

15. P
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16. 1981
Gerd Binnig and Heinrich Rohrer invented
the scanning tunneling microscope that gives
three-dimensional images of objects down to the
atomic level. Binnig and Rohrer won the Nobel
Prize in Physics in 1986. The powerful scanning
tunneling microscope is the strongest microscope
to date.

17. Scanning Tunnelling
Microscope and
images

18. Parts & Functions
of the
Microscope

19. The compound microscope uses lenses and light to enlarge
the image and is also called an optical or light
microscope. The simplest optical microscope is the
magnifying glass and is good to about ten times (10X)
magnification.

20. The compound microscope has two systems of
lenses for greater magnification, 1) the ocular, or
eyepiece lens that one looks into and 2) the
objective lens, or the lens closest to the object.

22. Eyepiece Lens: the lens at the top that you look through. They are usually
10X or 15X power.
Tube: Connects the eyepiece to the objective lenses
Arm: Supports the tube and connects it to the base
Base: The bottom of the microscope, used for support
Illuminator: A steady light source (110 volts) used in place of a mirror. If your
microscope has a mirror, it is used to reflect light from an external light
source up through the bottom of the stage.

23. Stage: The flat platform where you place your slides. Stage clips hold the slides
in place. If your microscope has a mechanical stage, you will be able to move the
slide around by turning two knobs. One moves it left and right, the other moves it
up and down.
Objective Lenses: Usually you will find 3 or 4 objective lenses on a
microscope. They almost always consist of 4X, 10X, 40X and 100X
powers. shortest lens is the lowest power, the longest one is the lens with the
greatest power.
Revolving Nosepiece or Turret: This is the part that holds two or more
objective lenses and can be rotated to easily change power.

24. Condenser Lens: The purpose of the condenser lens is to
focus the light onto the specimen. Condenser lenses are most
useful at the highest powers (400X and above).
Diaphragm or Iris: Many microscopes have a rotating
disk under the stage. This diaphragm has different sized holes
and is used to vary the intensity and size of the cone of light that
is projected upward into the slide

25. Proper Handling of the Microscope:
The are a number of important
procedures to follow when using a
microscope. Review the points that
follow.

26. 1. Always carry the microscope in an upright position with two
hands. One hand should support the base and the other should
be on the arm.

27. 2. Sunlight should not be used
as a source of light for
microscopes that have a
mirror rather than a
projection lens.

28. 3. Use lens paper and lens cleaning
solution to clean the lenses on the
microscope. Paper towel will scratch the
lenses. Use a soft cloth to
Clean other parts
Of the microscope.

29. 4. Always set your microscope on a clean, flat
surface.
5. Always remove slides from the stage and
rotate the nosepiece to the lowest power
before returning the microscope to its
storage area.