power point for biology

1. MICROSCOPE
- a microscope is an instrument that can be used to
observe small objects, even cells. the image of an object
is magnified through at least one lens in the microscope.
this lens bends light toward the eye and makes an
object appear larger than it actually is.

2. 1. OPTICALS MICROSCOPE - consists of only one lens
the simplest form of optical microscope consists of one double
convex lens with a short focal length. the lens is capable of
magnifying an object from 15x up to 2000x.
example: magnifying glass.
2. COMPOUND MICROSCOPE – uses visible light to produce
a magnified image of an object. this is composed of an
objective lens and ocular lens mounted at opposite ends of a
closed tube
TYPES OF MICROSCOPE

3. a) MONOCULAR COMPOUND MICROSCOPE – composed of one eyepiece.
b) BINOCULAR COMPOUND MICROSCOPE – composed of two eyepieces.
c) TRINOCULAR COMPOUND MICROSCOPE – composed of three eyepieces where one of the
eyepieces is a camera that takes the picture or projects that picture on a screen.

4. SPECIAL PURPOSE OPTICAL MICROSCOPES
• 1. STEREOSCOPIC MICROSCOPES – consists of two low-powered
microscopes arranged so that they converge on the specimen. these produce a
3-dimensional image that has its right side up.
• 2. ULTRAVIOLET MICROSCOPE – uses the ultraviolet
wavelength of the spectrum instead of the visible wavelength. lenses used may
be quartz or fluorine instead of glass.

5. 3. PETROGRAPHIC MICROSCOPE – this is a compound microscope which uses plane polarized
light and is used to identify and estimate the mineral content of igneous and metamorphic rocks.
4. DARK FIELD MICROSCOPE – uses lighting in the form
of hollow, very intense cone of light concentrated at the specimen

6. 5. BRIGHT FIELD MICROSCOPE – operates
through the reflection of light from objects to the
eyes

7. TYPES OF ELECTRON MICROSCOPES
1. SCANNING ELECTRON MICROSCOPE (SEM) – using electrons to light
objects, they can magnify from 100 000 up to a million times. the scanning probe
microscope can make atoms visible and capable of 3-dimensional image. other
types are scanning transmission electron microscope, electron probe micro
analyzer, and atomic force microscope.
2. TRANSMISSION ELECTRON MICROSCOPES (TEM) –
capable of up to 1 million times magnification.

9. MECHANICAL PARTS
• STAND – made of heavy foot and a horshoe-shaped based that supports th
microscope
• BODY TUDE – cylindrical part where the lenses are attached and can be
raised of lowered for better focusing.
• COARSE ADJUSTMENT KNOB – this is done first after the objective lens
is lowered near the object.
• FINE ADJUSTMENT KNOB – used sparingly for further focusing of the
object.
• STAGE – a platform with an opening to let the light pass where the
specimen in a glass silde is placed. a mechanical stage has a device for
controlled shifting of the slide.

10. OPTICAL PART
• STAGE CLIPS – keep the glass slide in place so that it
will not move.
• ARM – connects the base and the stage with the tube.
• DRAW TUBE –holds the eyepiece
• OBJECTIVES – lens located near the object, magnifies up to
90 times. May be low or high powered.
• EYEPIECE– located at the top of the body tube. It is the part
where you peep during observation.

11. • REVOLVING NOSEPIECE – MAY BE SINGLE, DOUBLE,
OR TRIPLE-LOCATED AT THE BOTTOM OF THE BODY
TUBE WHICH CARRIES THE MAGNIFYING LENSES OR
OBJECTIVES.
• MIRROR – USED TO FOCUS THE RAYS OF THE LIGHT
SOURCE TOWARD THE OBJECT.
• DIAPHRAGM – CONTROLS THE LIGHT THAT ENTERS
THE STAGE OPENING.
• CONDENSER LENS – USED TO FURTHER CONTROL
THE LIGHT AS NEEDED.