Video Transcript
Which part of a microscope allows
for the magnification to be adjusted?
To answer this question, let’s
review some key facts about the microscope and how it gives a magnified image of an
object.
First of all, what is
magnification? Magnification is the process by
which an object is made larger in appearance. This is useful if we want to look
at an object that is not visible to the naked eye, such as a cell. We could use a microscope to look
at the cell. This is a diagram of a common light
microscope used in schools. The common light microscope uses
two magnifying lenses to give a magnified image of an object. So, let’s see how this works.
The object that is going to be
looked at is placed on a glass slide. The slide is then placed on the
stage. Light is then emitted from the
light source below the object. The light then passes through the
object on the slide and enter the first of two magnifying lenses. As it is the lens closest to the
object, it is called the objective lens. This lens magnifies the object to
form an image. The light from this image then
passes through the second of the lenses, found in the eyepiece. So, it is called the eyepiece
lens. As the light passes through the
eyepiece lens, the image is magnified again to form the image that we see when we
look through the eyepiece.
There are usually three or four
objective lenses attached to a revolving nosepiece. These objective lenses are most
often of magnification strengths times four, times 10, times 40, and times 100 on
the school microscopes. You should always start by
observing the object through the lowest-power objective lens. And then you can work steadily up
through the powers, focusing the object each time a new lens is used.
The size of the image seen depends
on the strength of the lenses used. For example, if you used an
objective lens of times four, this magnifies the image by four. And then if the eyepiece lens has a
strength of times 10, this will magnify it to further 10 times. This means that the total
magnification of the image is four multiplied by 10, which gives us times 40.
The eyepiece is usually kept the
same in the microscope. But because the objective lenses
can be easily rotated around on the revolving nosepiece, you can change the
magnification of the final image using these. If you use the most powerful
objective lens, the total magnification would be 100 times 10, which gives us times
1000.
We now have enough information to
answer our question correctly. The part of a microscope that
allows for the magnification to be adjusted is the objective lens.
