ICT PRESENTATION.pptx about microbiology

On Microbiology

1. MICROSCOPY CLASS 3R d SEMESTER DEPARTMENT CHEMICAL ENGINEERING FA23-CHE-035 HASEEB AKRAM

2. CONTENTS Historical development of microscopes Microscope and it's types Resolution and magnification Limitations of optical microscopy

3. M - Magnify I - Illuminate C – Clarify R – Resolve O – Observe Objective : S – Study C – Characterize O – Obtain P – Precise Y – Yield In short, microscopy aims to precisely observe, study, and characterize tiny structures or samples, yielding valuable information and insights.

4. History of microscope 1280 A.D : First modern application of optics 1590 first compound microscope, using two convex lenses 1609 : Galileo Galilei improves the design. 1667: Robert Hooke used a compound microscope to look at cork and 1676 : discovery of microorganisms using a handmade microscope,

5. CONTINUED: 18th-19th centuries: Microscope design advances with the introduction of achromatic lenses, improving image quality and magnification . 20th century: Ultra microscope was invented by Richard Zsigmondy (1903). Electron microscopes (1931) . Phase- contrast microscope was invented (1932), and scanning tunneling microscopes (1981) are developed, enabling scientists to study structures at the atomic level.*Present day*: Modern microscopes use advanced technologies like fluorescence, super-resolution, and artificial intelligence to push the boundaries of scientific discovery .

6. Microscope techniques by which investigations are made on fine details that cannot be discerned with the naked eye. covers techniques of observation. the imaging of atoms provides information about the structure chemical composition of objects.

7. WORKING PRINCIPLE Light Source: Light shines through the condenser lens.   Sample Illumination: The light focuses on the sample.   Image Creation: The sample changes the light, making a blurry image. Magnification: The objective lens makes the blurry image clearer. Final Image: The eyepiece makes the clear image bigger, so you can see it.

8. Types of microscope There are Three main types of microscope Optical Microscope Electron Microscope Scanning Microscope

9. ELECTRON MICROSCOPE: An electron microscope is a scientific instrument that uses a beam of electrons as a source of illumination to produce magnified images of samples. Electron microscopes have a much higher resolution than light microscopes, up to 0.1 nanometers (nm), due to the shorter wavelength of electrons.

10. Basic principle: A beam of electrons is formed by the Electron Source and accelerated toward the specimen using a positive electrical potential. The electron beam is confined and focused using metal apertures and magnetic lenses into a thin, focused, monochromatic beam. Electrons in the beam interact with the atoms of the specimen, producing signals that contain information about its surface topography, composition and other electrical properties. These interactions and effects are detected and transformed into an image

11. Types of electron microscope: There are two main types of electron microscopes: - Transmission Electron Microscope (TEM) : Electrons pass through the sample, producing a 2D image. - Scanning Electron Microscope (SEM): Electrons scan the sample's surface, producing a 3D image.

12. MAGNIFICATION It is the ratio of the size of an object in an image produced by an optical system to the actual size of the object itself, the upper limit of visual magnification depends on the maximum resolving power of the microscope system. PRINCIPLE: A microscope enlarges the view of an object by enlarging it twice using the objective and ocular Lenses . It happens in the following way: Light from below a specimen illuminates it. An objective lens placed very closed to the specimen produce a ‘real image’ of the specimen . A real image A formed by an objective lens is magnified by an eyepiece lens and viewed as a virtual image

13. RESOLUTION The resolution of an optical system is its ability to distinguish two objects from one another, when they are in proximity. We use the Rayleigh criterion, which states that in order to resolve two points they must be no closer together than the distance from the center of the PSF to the first destructive interference band in the diffraction pattern PRINCIPAL: Resolution is the ability to distinguish two objects from each other. The resolving power of microscope is the most important feature of the optical system and influences the ability to distinguish between fine details of a particular specimen. Electron microscope has low wavelength, so have more resolving power.it different from magnification just because it also tells internal details about object.

14. Limitations of Optical Microscopy Optical microscopy is a very useful technique to examine the appearance of a sample with greater detail, but there are some limitations that provide a boundary to its use in practice. Resolution limit of optical microscopes : When an optical microscope with transmitted light is used at very high magnifications, the image of point objects may be distorted. They may be seen as fuzzy discs that are surrounded by diffraction rings, known as Airy discs. These diffraction rings limit the ability of the optical microscope to resolve fine details of the sample. The resolving power of an optical microscope is a measure of the ability of the microscope to distinguish between two adjacent structural details, without the interference of Airy discs.

15. Low magnification The maximum magnification that can be achieved by an optical microscope typically ranges from 500x to 1500x. While this level of magnification has many purposes and can be for number of practical applicat ions, it is considerably lower than the magnification that can be achieved with electron microscopy. In contrast, an electron microscope may be able to providemagnifications greater than 160,000x. As a result, the low magnification of an optical microscope is a limiting factor for some Applications, when an electron microscope may be better option Poor surface view Similar to the magnification limitation of optical microscopy, the surface view of the sample with an optical microscope is sufficient for many purposes, but can be a limiting factor. It is significantly less clear than what can be achieved with an electron microscope, and this alternative may be preferred in some situations. This does not limit its use for many applications though i.e. when high resolution with a clear surface view is not necessary. However, in some instances electron or another type ofmicroscopy may be better suited to the purpose to achieve