A simple microscope is made with the use of a magnifying lens. A “loupe” is the lens that is used to see through a simple microscope. The most common simple microscope is the magnifying lens.

 Simple microscopes are used in biological labs and dermatological investigations as a part of experiments by students and are extensively used by jewellers for identifying real jewellery and diamond cuts.

The image formed by a simple microscope is virtual and erect, unlike a telescope. A convex lens makes the image appear taller than the real image, as a convex lens has a shorter focal length.  

The Invention of the Simple Microscope

The invention of the simple microscope is attributed to Hans and Zacharias Janssen in 1509, who was also a precursor to the invention of two types of microscope, the compound microscope and the simple microscope. In 1676 Antonie van Leeuwenhoek invented the simple biconvex lens microscope with a power of 70X to 275X.

Parts of a Simple Microscope

• The base: The whole microscope is mounted on the base
• Stage and the stage clips: This is where the specimen is kept for observation, and the clips hold the sample in position
• Eyepiece: It is the lens through which one sees the sample
• Tube: The tube connects the eyepiece and the objective 
• Objective lens: The objective lens is the lens used for magnification. The objective lens is colour coded for the reference of magnification, 10X, 40X 
• Nose piece: The nose piece is revolving and is known as the turret
• Diaphragm: The diaphragm controls the light that passes through the stage
• Coarse and fine adjustment knobs: Two knobs that can be used for adjustment or fine-tuning of the focus
• Condenser: It is used for focussing the light on the sample

Working of the Simple Microscope

• A simple microscope is made up of a magnifying lens
• When a tiny object is placed within the focus, the image formed is virtual and erect
• The convex glass provides a magnified image of the object
• The image is formed at the reference seeing distance, to the eye seeing through the lens

Magnification Quotient of the Simple Microscope

• The magnification of a simple microscope is very limited as it is only a single objective lens
• The maximum magnification in a simple microscope is usually limited to 10X power
• The equation used to denote the magnification of the lens is denoted by:

When the image is formed at the near point

M=1+ D/f

When the eye is placed behind the lens at a distance

M=1+(D-a)/ f

When the image is formed at infinity

M= D/f

D= shortest reference seeing distance

f= focal length of the objective lens

It implies that the shorter the focal length of the lens, the higher the magnifying power of the microscope. 

Applications of a Simple Microscope

1. Using for laboratory purposes
2. Using by jewellers to check diamonds and designs
3. Used by archaeologists to read inscriptions
4. As an added equipment during experiments

Conclusion 

The invention of the simple microscope has led to greater discoveries for humankind. The official discovery of the microscope is attributed to Antonie van Leeuwenhoek in 1676. A simple microscope is made of a single converging lens which makes an erect and virtual image of the object. The optical parts of the simple microscope are a lens and a mirror. The other parts are the eyepiece, nose piece, stage, stand and base. Simple microscopes are used in biological labs to study tiny organisms by jewellers, archaeologists etc.