You must have played with a magnifying glass in your childhood and maybe, used it in school projects to burn paper from the heat of the sun. It includes a convex lens which is mounted on a frame with a handle to hold. Hence, it is also termed a hand lens. It is placed over the object to obtain a magnified image of that object. But, how does a magnifying glass work? Let’s find out!
1. Who Invented the Magnifying Glass?
To see things closely and overcome the problems of weak eyesight, a magnifying glass was invented by an Englishman, Roger Bacon, in Oxford, UK, around the 13th century. He was one of the Franciscan friars and also, a scholar. Around the same time, eyeglasses were developed in Italy too. Although the exact year of this invention is not clear, pieces of evidence mention its use in the year 1268. Roger Bacon initially used them as basic spectacles since it helped scientists with failing eyesight to carry on with their work.
2. What are the Different Types of Magnifying Glass?
Depending upon the type of work, magnifying glasses can be of 4 kinds, namely:
- Glass lenses are simple magnifying glass made as spherical biconvex.
- The magnifying glass with reduced image quality is known as Fresnel lenses. They are large in size. For example, thin sheet magnifiers.
- The ones used for spectacles are known as plastic optics.
- Aplanatic glasses have two plano-convex lenses, with the convex surface facing the inner side. They have low image distortions and therefore are used as reading glasses. (See What a short-sighted person sees?)
3. What Kind of Lens is Used?
A convex lens is used in the magnifying glass. Convex means curved outward. The back of the spoon can be taken as an example of how a convex lens looks like. It causes light rays to converge and come together. In order to make things appear bigger, some magnifying glasses use two convex lenses. It allows light to pass through it and then, bends it accordingly. convex lenses have the ability to bundle all parallel rays to one point. And the point formed where all these rays get together is the focal point.
4. How do Eyes Work?
In order to understand the phenomenon of a magnifying glass, we should first understand how our eyes work. Every object reflects the light that falls on it. These rays then enter the retina of our eyes and create a high and a low point at a certain angle to each other. Now the distance between these high and low points of light makes our eyes see the image of that object. Then our eyes interpret these rays and determine the size of the objects. And thus, the size of the image perceived by our eyes is the real image, also known as the Inverted real image. (See Personality & characteristics of people with brown eyes)
5. How Does a Magnifying Glass Work?
The magnifying glass works on the simple principle of optical physics. Just like the shape of our cornea, the convex lens is also curved inside and bulged outside. Light when passes through a magnifying glass is not directly absorbed by our eyes. The rays that enter the magnifying glass bend a little due to the convex lens. Then, they converge on the retina of our eyes. This image perceived by our eyes is the magnified image, known as a Virtual image. This answers the question of how does a magnifying glass work. (See How Calculator Works?)
6. How does Distance affect Image?
The distance between eye and object determines magnification. If the distance between the object and the magnifying glass is more, then the image seen will be flipped viz upside down. You can achieve maximum magnification value by moving the magnifying glass between the object and the eye until you see a large focused image. (Also See: How Sunglasses affect your mood?)
7. What are its Common Uses?
The principle behind magnifying glass is used in telescopes as well as microscopes to view outer space and microorganisms, respectively. It is also used in spectacles to see smaller objects or objects at a farther distance better.
We know how does a magnifying glass work which is quite similar to how our eyes work. We also know about the parts & uses of a magnifying glass.