# Microscopy

## Microscopy

Microscopy is an essential tool in laboratories that helps us magnify samples like cells and tissues, making it possible to view things that are too small to see with the naked eye. There are many kinds of microscopes, but the two most common types are light and electron microscopes. These microscopes are widely used in labs to help scientists study and understand the world around us. Without microscopy, biology as we know it would not be possible.

## Microscope Magnification and Resolution

When examining a structure under amicroscope, there are two things that are crucial to remember:

1.      Magnification

2.      Resolution

Magnification specifies how much an objecthas been magnified, while resolution describes a microscope's capacity to tellapart two similar points (objects).

## Unit conversions

Below is the unit conversion table for the units used in microscopy and it might be useful to learn these:

### Examples

Suppose we want to find out the actual length of a cheek cell. We know that under the microscope, the length of the cell appears to be 10 mm at a magnification of 12,500X. To calculate the actual length, we first convert 10 mm to µm, which is 10,000 µm (remember 1 mm = 1,000 µm). Then we rearrange the equation to calculate the actual length, which is the length of the image divided by the magnification. By plugging in our values, we get:

Actual length = 10,000/12,500 = 0.8 µm

So the actual length of the cheek cell is 0.8 µm.

## Light microscope and Electron microscopes differences

Light microscopes can only magnify objects to a certain extent without sacrificing resolution. Their magnification range typically falls between 1,000 to 1,500X, which is far lower than that of electron microscopes. Electron microscopes, on the other hand, can magnify objects up to a staggering 1,000,000X! Additionally, light microscopes have a resolution limit of 200 nm, while electron microscopes can achieve a remarkable resolution limit of 0.2 nm. The difference between the two types of microscopes is truly remarkable!

## Parts of a light microscope:

### Stage

You will place your specimen on thisplatform (usually on a glass slide). Using the stage holding clips, you can fixthe specimen in place.

### Objective lenses

To enlarge the image, the objective lenseswill collect the light that is reflected from your specimen.

### Eyepiece

At this stage, you can see your own image.The image created by the objective lens is magnified by the ocular lenses inthe eyepiece.

### Course and fine adjustment knobs

Using the microscope's coarse and fin adjustment knobs, you can change the focus of your enlarged image.

### The source of light

Your specimen is illuminated artificially by the light source, also known as the illuminator. The strength of the light beam can be changed using the light intensity control.

## Specimen preparation for microscopy

To ensure that the enlarged image producedby your chosen microscope is accurate, your sample specimen must be carefully prepared.

### Preparation for light microscopy

There are two primary sample preparation techniques used in light microscopy: wet mounts and fixed specimens. Wet mounts involve placing the specimen on a glass slide and adding a drop of water to create a wet mount. A cover slide is often placed on top to fix it in place. For fixed specimens, the sample is affixed to the slide using chemicals or heat, and the cover slide is then positioned on top. The specimen can be chemically fixed by adding chemicals like ethanol and formaldehyde.

When using a microscope, the image's magnifying and resolving power are crucial factors that determine how it appears to the eye. These two factors are closely linked. The primary microscope used to instruct pupils is the light microscope, while electron microscopes are often used by scientists when examining incredibly microscopic structures. Compared to optical microscopes, electron microscopes offer significantly higher resolution. It's important to remember that your field of vision, or what you see when you look through your eye's lens, is what the microscope can see.

## Microscopes

How do you calculate magnification on amicroscope?
Magnification = length of image/actual length

How do microscopes work?
Microscopes work by using multiple concave lenses that make images appear bigger.

How does the lens of a light microscope work?

Light microscopes use two types of lenses: objective and ocular. Objective lenses gather reflected light from your specimen to magnify the image. Ocular lenses simply magnify the image produced by the objective lens.

What are the five different types of microscopes?
There are many types of microscopes but five examples include: Light microscope, Electron microscopes, X-ray microscope, Scanning probe microscope, Scanning acoustic microscope

What are the two main types of electron microscopes?
Transmission electron microscope (TEM) and scanning electron microscope (SEM).