MICROSCOPE PRESENTATION

Maha Monfared Grade 9A 24/5/2022 Physics

The world of microscopes

Q1: What Are microscopes?

What are microscopes?

A microscope (from Ancient Greek (mikrós) 'small', and (skopéō) 'to look (at); examine, inspect') is a laboratory instrument used to examine objects that are too small to be seen by the naked eye. Microscopy is the science of investigating small objects and structures using a microscope. Microscopic means being invisible to the eye unless aided by a microscope.

-Robert Hooke (inventor of the compound microscope)

"By the help of microscopes, there is nothing so small, as to escape our inquiry; hence there is a new visible world discovered to the understanding."

Q2: What Are The types of microscopes?

• Simple microscope
• Compound microscope
• Electron microscope
• Stereomicroscope
• Scanning probe microscope

In this presentation, we will be learning about simple, compound, and electron microscopes.

Types of microscopes

• A simple microscope is a magnifying glass that has a double convex lens with a short focal length. Examples of this kind of instrument include the hand lens and reading lens. When an object is kept near the lens, then its principal focus with an image is produced, which is erect and bigger than the original object. The image formed is virtual and cannot be projected on a screen like a real image.

What are Simple Microscopes?

• A compound microscope is considered to be one of the standard microscopes that can be used for general purposes. The arrangement of the lens is such that it magnifies the objects from the complex system.

There are two types of lenses that are used in the compound microscope:

• The objective lens is placed close to the object that needs to be examined. (forms a real inverted image of the image inside the body tube)

• The eyepiece allows the image to be viewed. The eyepiece is also known as the ocular lens. The image of microscopic objects can be viewed through these lenses. (There are four types of magnification that can take place in the ocular lens:5X, 10X, 15X, 20X)

What are Compound Microscopes?

• 1 objective lens
• Has a small hollow cylindrical knob attached to the base which is used to hold the microscope
• Has one adjustment screw used for focusing by moving the limb up and down
• Concave reflecting type is used

• 2 to 4 objective lens
• Has a curved knob which is used to hold the microscope
• Has a coarse adjustment screw for fine and sharp focus
• Plane on one side and the other side is concave

Simple Microscope

Compound Microscope

VS

Fine salt

• An electron microscope is a microscope that uses a beam of accelerated electrons as a source of illumination. It is a special type of microscope having a high resolution of images, able to magnify objects in nanometres, which are formed by controlled use of electrons in a vacuum captured on a phosphorescent screen. (luminescence that is caused by the absorption of radiations)

There are two types of electron microscopes:

• The transmission electron microscope (TEM)(higher res, magnified up to 50M times, broad electron beam, image taken of internal structure.)
• The scanning electron microscope (SEM) (lower res, magnified up to 2M times, fine focused beam, image taken from surface)

The main difference between SEM and TEM is that SEM creates an image by detecting reflected or knocked-off electrons, while TEM uses transmitted electrons (electrons that are passing through the sample) to create an image.

What are Electron Microscopes?

Everyday objects under an electron microscope

There is a totally different world under an electron microscope. Here are some everyday objects under an electron microscope.

ThankYou!