Difference Between Simple And Compound Microscope


What is a Simple Microscope?

A simple microscope, also known as a single-lens microscope or a magnifying glass, is a basic optical instrument used to magnify small objects or details of objects that are otherwise difficult to see with the naked eye.

A simple microscope consists of just one convex lens. This lens is typically a biconvex lens, which means it is curved outward on both sides, causing light to converge and form an enlarged virtual image of the object being observed.

Simple microscopes are commonly used for tasks like reading fine print, examining small objects, inspecting jewelry or coins, and conducting basic scientific observations. They are portable, easy to use, and do not require extensive technical knowledge.

When an object is kept near the lens, then its principal focus with an image is produced, which is erect and bigger than the original object. The image formed is virtual and cannot be projected on a screen like a real image.

A simple microscope works on the principle that when a tiny object is placed within its focus, a virtual, erect, and magnified image of the object is formed at the least distance of distinct vision from the eye held close to the lens.

Uses of Simple Microscope

  • It is used in pedology (a study of soil particles)
  • It is used by a dermatologist to find out various skin diseases.
  • It is used in microbiology to study samples of algae, fungi etc
  • It is used by the jewellers to get a magnified view of the fine parts of the jewellery.
  • It is used to see the magnified view of different particles of different types of soils.
  • Palmists use it to see an enlarged view of the lines of our hands.
  • Skin specialists use it to find out various diseases of the skin.
  • It is also used to see the details of stamps and engravings.

What is a Compound Microscope?

A compound microscope is an upright microscope that uses two sets of lenses (a compound lens system) to obtain higher magnification. In other words, A compound microscope is a high power (high magnification) microscope that uses a compound lens system. A compound microscope has multiple lenses: theobjective lens(typically 4x, 10x, 40x or 100x) is compounded (multiplied) by theeyepiece lens(typically 10x) to obtain a high magnification of 40x, 100x, 400x and 1000x.

A compound microscope is considered to be one of the standard microscopes that can be used for general purposes. The arrangement of the lens is such that it magnifies the objects from the complex system.

There are two types of lenses that are used in the compound microscope:

  • The objective lens is placed close to the object that needs to be examined.
  • The eyepiece allows the image to be viewed. The eyepiece is also known as the ocular lens.

The light is made to pass through the thin transparent object. A magnified image of the object is obtained by the objective lens. This image is known as the real image. The eyepiece or the ocular lens then magnifies the real image more and is viewed as the virtual image. The compound microscope is also known as the bright-field microscope because the light passes directly through the light source to the eye through the two lenses. This mechanism makes the field of vision brightly illuminated.

Uses of Compound Microscope

  • The identification of diseases becomes easy in pathology labs with the help of a compound microscope.
  • Forensic laboratories use compound microscopes for the detection of human fingerprints.
  • The presence of metals can be detected with the help of a compound microscope.
  • The study of bacteria and viruses becomes easy with the help of a compound microscope.
  • Schools use compound microscopes for academic purposes.

Components of a compound microscope

  • Objective Lens: The objective lens is the primary lens closest to the specimen being observed. It gathers and magnifies light from the specimen and forms an initial real, inverted image. Compound microscopes typically have multiple objective lenses with varying magnification levels (e.g., 4x, 10x, 40x, 100x). Users can switch between these objectives to achieve different levels of magnification.
  • Eyepiece (Ocular Lens): The eyepiece, or ocular lens, is the lens you look through when using the microscope. It further magnifies the image produced by the objective lens. Eyepieces often have a standard magnification of 10x.
  • Tube: The tube connects the eyepiece to the objective lenses and ensures proper alignment of the optical components.
  • Revolving Nosepiece: This is a rotating device that holds multiple objective lenses. It allows users to switch between different objectives easily.
  • Stage: The stage is a platform where the specimen is placed for observation. It often includes a mechanical stage with knobs for precise movement of the specimen in both the X and Y directions.
  • Condenser: The condenser is located beneath the stage and is used to focus and concentrate light onto the specimen. It may have an adjustable diaphragm to control the amount of light reaching the specimen.
  • Illumination Source: Compound microscopes can be equipped with various light sources, such as tungsten or LED bulbs, to illuminate the specimen. Some microscopes also offer options for transmitted or reflected light illumination, depending on the type of specimen being observed.
  • Coarse and Fine Focus Knobs: These knobs allow for precise focusing of the image. The coarse focus knob is used for initial rough focusing, while the fine focus knob provides finer adjustments to achieve a sharp image.

Simple vs Compound Microscope: Key Takeaways

Points of ComparisonSimple MicroscopeCompound Microscope
Invented byAround 1670, Antony van Leeuwenhoek invented the first simple microscope.Hans and Zacharias Janssen invented the first compound microscope in 1950.
Number of lensesA single lens can be used to view objects.The term “compound” refers to the use of numerous (3 to 5) lenses in a microscope.
Condenser lensA condenser lens is not present in simple microscopes.A condenser lens is included in the compound microscope.
Light sourceIn basic microscopes, the light source is natural.When tiny objects need to be seen, an illuminator is used as a light source.
Mirror typeA concave mirror is used in a basic microscope.On one side of a compound microscope, a plane mirror is used, while on the other, a concave mirror is used.
Level of magnificationThe simple microscope’s entire magnification is restricted to one lens.The total magnification of a compound microscope is the combination of the objective lens and eyepiece magnifications.
Magnifying power           The simple microscope’s entire magnification is restricted to one lens. Up to 300X magnification.The total magnification of a compound microscope is the sum of the objective lens and eyepiece magnifications. Up to 2000X magnification.
Adjusting MagnificationIt just has one adjustment screw that allows you to move the limb up and down to focus on the object.Coarse Adjustment: This is used to focus on an object quickly.Fine Adjustment: It is used to focus on objects in a fine and crisp manner.
StructureThe microscope is held by a small stand that is hollow cylindrical and connects to the base.The microscope is held in place by a curved arm.
UseSimple microscope is used at a basic level, where there is no rigorous requirement of research.Due to an added lens to a compound one, professionals use this for research purposes.
ApplicationOnly useful for minor tasks like magnifying small letters while reading.Has a wide range of applications, including analysing the structure of various objects, such as cells in live organisms

Key Takeaways

  • A microscope is typically a laboratory instrument used to magnify tiny things to be made visible to the naked eye, which would have been invisible without the aid of a microscope.
  • A compound microscope is a high power (high magnification) microscope that uses a compound lens system.
  • A simple microscope is one that uses a single lens for magnification, such as a magnifying glass.
  • A simple microscope is essentially a magnifying glass made of a single convex lens with a short focal length, which magnifies the object through angular magnification, thus producing an erect virtual image of the object near the lens.
  • The magnifying power formula of a simple microscope is M = 1 + D/F, where D is the least distance of the distinct vision and F is the focal length of the convex lens.