Login

Introduction to the Compound Microscope: Parts & Uses

An error occurred trying to load this video.

Try refreshing the page, or contact customer support.

Coming up next: What Are Elements?

You're on a roll. Keep up the good work!

Take Quiz Watch Next Lesson
 Replay
Your next lesson will play in 10 seconds
  • 0:03 The Compound Light Microscope
  • 1:50 Parts of the Microscope
  • 4:18 Clarity and Overall Structure
  • 5:31 Lesson Summary
Add to Add to Add to

Want to watch this again later?

Log in or sign up to add this lesson to a Custom Course.

Login or Sign up

Timeline
Autoplay
Autoplay
Create an account to start this course today
Try it free for 5 days!
Create An Account

Recommended Lessons and Courses for You

Lesson Transcript
Instructor: Sarah Friedl

Sarah has two Master's, one in Zoology and one in GIS, a Bachelor's in Biology, and has taught college level Physical Science and Biology.

The compound light microscope is a useful tool in any biology laboratory. In this lesson, you'll be introduced to the parts of a compound microscope, as well as understand the function of each of those parts.

The Compound Light Microscope

As we get older, our eyes are not able to see things as clearly, especially things that are small. We may get a magnifying glass in order to help us read and see small objects, and this helps because magnification makes the object appear bigger so we see it more clearly.

A microscope does the same thing, but for very, very small objects. The most common type of microscope you'll use in your biology labs is a compound light microscope. This microscope has two lenses that bend light so that a specimen is magnified and projected. Having two lenses is very important because this is where the microscope gets its name. To compound something means to add to it - like compound interest, or a chemical compound, which is a sum of multiple parts. The word microscope is also key, because micro means small and scope means view.

You may have noticed the word 'light' in the name of this microscope, and that's also no accident. This type of microscope uses visible light, which is the part of the light spectrum our eyes can see, and passes it through the lenses. The lenses bend the light so that the object you're looking at appears larger than it is. This allows you to see it better.

The resolution, or clarity of an image, is also an important factor when looking through a microscope. A standard compound microscope can magnify objects about 1,000 times, which is pretty good! But above this the image becomes blurry, so even if an image appears larger it may still not be very clear unless the resolution is good.

Compound light microscopes have been around for quite some time now. They were first used in the 17th century. It's no coincidence that during this same time cells were discovered, which led scientists to a great number of other discoveries about microorganisms and cell structure and function.

Parts of the Microscope

Microscopes are very powerful tools indeed, but in order to use one properly, you need a basic understanding of its components. Quite possibly the most important part of the compound light microscope is, well, the light source! Ok, maybe the power switch is the most important part because that is what allows you to have light in the first place. But the light source is definitely next on the list of important parts! It is found at the base of the microscope and you can adjust the brightness of the light by rotating the light source knob.

Moving up from the light source we find the stage. This is directly over the light source and is a flat area that holds your slide or specimen flat. On the stage, we find the aperture, which is a small hole in the stage that allows light to pass through. Whatever part of your slide or specimen is directly over the aperture is what you'll see when you look through the microscope.

Also on the stage are the stage clips. These are used to hold your slide in place, and they simply clip over the edges of your slide to hold it down. There will be a knob near the stage called the stage control that moves the stage clips so that you can look at different parts of your slide without having to move it by hand.

As we continue to move up from the base of the microscope we find the objective lenses, which are attached to the nosepiece. The objectives are how much the image is magnified, and the number is written on the side of each objective with a number and the letter X. For example, if you see 10X on the side of an objective, this means that the object is magnified 10 times. Most compound microscopes have 3 or 4 objectives, and they will most likely be 4X, 10X, 40X, and 100X. The nosepiece adjusts so that you can turn from one objective to the other, depending on how much magnification you need for your specimen.

Above the objective lenses is the body tube, which is connected to the eyepiece. The eyepiece is what you actually look through to see your specimen, and the body tube connects this to the objective lenses. The eyepiece is yet another point of magnification, so while your objectives have a magnification of 4, 10, 40, or 100 times, the total magnification of the microscope is this multiplied by the magnification of the eyepiece. Usually, the eyepiece magnifies objects 10 times their size, so if you combine this with the objective lens magnifications, you would have a total microscope magnification of 40X, 100X, 400X, and 1000X.

Clarity and Overall Structure

In order to get the best image possible, there are two knobs that you should be aware of. One is the coarse adjustment knob and the other is the fine adjustment knob. The coarse adjustment knob does just what is says - it allows for broad, coarse adjustment of the image. Once you get the image in about the range of focus that you need, you can use the fine adjustment knob to get it just right.

To unlock this lesson you must be a Study.com Member.
Create your account

Register for a free trial

Are you a student or a teacher?
I am a teacher
What is your educational goal?
 Back

Unlock Your Education

See for yourself why 30 million people use Study.com

Become a Study.com member and start learning now.
Become a Member  Back

Earning College Credit

Did you know… We have over 95 college courses that prepare you to earn credit by exam that is accepted by over 2,000 colleges and universities. You can test out of the first two years of college and save thousands off your degree. Anyone can earn credit-by-exam regardless of age or education level.

To learn more, visit our Earning Credit Page

Transferring credit to the school of your choice

Not sure what college you want to attend yet? Study.com has thousands of articles about every imaginable degree, area of study and career path that can help you find the school that's right for you.

Create an account to start this course today
Try it free for 5 days!
Create An Account
Support