Can microorganisms be seen with the naked eye? If not, how can they be seen?

AcademicBiologyNCERTClass 8

A microorganism or microbe is an organism that is microscopic, which means too small to see with the naked eye. They can be observed with the help of a simple microscope or compound microscope.

A light microscope uses visible light and lenses to detect and magnify objects. Depending on the number of lenses there are two types of microscopes such as simple light microscope and compound light microscope.


Parts of a Compound Microscope can be categorized into two, such as Mechanical parts and Optical parts.


(A) Mechanical Parts

1. Base: It is a U-shaped structure that supports the compound microscope.

2. Pillar: It is a vertical projection which supports the stage.

3. Arm: It is a curved structure for handling the compound microscope.

4. Stage: The flat and rectangular plate on which specimen is placed for examining. The center of the stage has a hole for light to pass through it.

5. Inclination joint: It is a joint between arm and pillar. The microscope can be tilted using it.

6. Clips: The stage is connected with two clips which can hold the slide.

7. Diaphragm: The diaphragm is present below the stage which can control and adjust the intensity of light. The diaphragm is of two types such as Disc diaphragm and Iris diaphragm

8. Nose piece: It is a circular and a rotating metallic part that has three holes for the objective lenses.

9. Body tube: The body tube is a hollow and tubular structure that can be moved up and down with the adjustment knobs.

10. Fine adjustment knob: It is the small knob used for sharp and fine focusing of the object.

11. Coarse adjustment knob: It is a large knob used for moving the body tube for exact focusing of the object.


(B) Optical Parts of a Compound Microscope

1. Eyepiece lens or Ocular: A lens place at the top of the body is an eyepiece. It is used to observe the magnified image

2. Mirror: Concave mirror is used to reflect light rays into the microscope. It is attached to the pillar or arm.

3. Objective lenses: Objective lenses are present at the bottom of the body tube which is connected to the revolving nose piece. The objective lenses are Oil immersion objective – 100X, High power objective – 45X, Low power objective – 10X.

Updated on 10-Oct-2022 12:46:41