The best way to understand how a microscope works is by knowing its parts. Those of a common microscope would do and learning them will only take a few minutes of your time. Afterwards, you could be using a polarized light microscope or a phase contrast microscope and you’ll still understand its mechanics almost instantly.

Getting to Know the Major Parts of a Common Microscope

Eyepiece – A microscope’s eyepieces have optical properties able to virtually magnify the image of your sample or specimen. This image can’t actually be seen by the naked eye but the eyepiece will successfully convert it into something you can see. There are different kinds of eyepieces used for microscopes and which one you use generally depends on what kind of sample you’re using and exactly which characteristics of the sample you wish to observe. An eyepiece doesn’t have the power of improving the microscope’s objective resolution but it can negatively affect the image if it’s poorly designed.

Objectives – Speaking of objectives, this part is one of the most important components of your microscope. Without it, you won’t be able to see anything. It’s best to think of it as the “horsepower” of your microscope. Thus, the higher resolution for your objectives, the better!

A microscope normally gives you three to five magnifying resolutions to choose from. If there’s a polarizer, the objective’s what allows polarized light to pass through. A microscope’s objectives are generally placed on top of the objective holder. If the latter’s rotating, you can change magnification effortlessly. Objectives are tiny and sensitive so be very careful in handling them.

Stage – This is the foundation for the sample being observed and not for the entire microscope. You must always keep your stage properly positioned and in its original shape. Anything else will give you a distorted view of the sample. Stages may be built-in or just attached and interchangeable. The stage of a microscope also contains a pair of stage clips or more to hold glass slides in place.

Coarse Adjustment Knob – This is often the first knob used for adjusting and it controls the movement or positioning of your microscope’s stage or body tube or both, depending on the microscope model you’re using. It does this with the help of your microscope’s pinion assembly and rack.

Condenser – Not many people are aware of the use or even the existence of the condenser in a microscope. This is unfortunate as the condenser’s just as important as the microscope’s objectives. The main function of a microscope’s condenser lenses are to concentrate, control, and collect the light coming from the microscope’s lamp. Depending on the microscope model, the condenser can be adjusted to provide specialized images using phase contrast, polarization, and other techniques. You may also find a condenser focus knob to adjust the condenser’s vertical height.

Fine Focus Knob – If the coarse knob is to adjust manual positioning of a microscope’s stage and body tube, the fine knob is used for the manual positioning of the sample or specimen. This must be handled very carefully as well since damaged fine focus knobs can cost a lot to replace. Damaged ones can also drastically affect viewing of your sample for the worse. Scientists tend to use fine focus knobs more frequently than coarse knobs.

Iris or Diaphragm – Basically, a microscope’s diaphragm determines just how much light should pass through to reach the sample. Less light being used will surprisingly mean a clearer image of the sample. When adjusting the diaphragm, take into consideration the transparency of your sample, the contrast level you desire, and the type of objective lenses you’re using.

Body Tube – This part of the microscope is what’s supporting the objectives and eyepiece. The body tube must be firmly attached and built sturdily. Most microscopes manufactured at present possess body tubes that have a maximum of 170mm in length.

Eyepiece Tube – This is simply where the eyepiece is inserted.

Filter Holder – This part is attached beneath the microscope’s condenser and is mainly responsible for how images are being filtered.

Foot or Base – This is the foundation of your microscope. In most cases, the foot is also where your light lamp is located.

Limb or Arm – The microscope’s arm is attached to the foot, unlike normal human body parts. It serves as a support to the body tube. There are various designs for a microscope’s arms.

Mirror or Lamp – This is where light used for your microscope comes from. For electron microscopes, this is called the electron source or gun.

Nosepiece – This is also known as the rotating objective changer and where objectives are placed.

These are the major parts of a common microscope. Know and understand what each stands for and you’ll be able to use just about any type of microscope.