Zoology First Lab - The Microscope PDF

ZOOLOGY First LAB. ms. Rasha mohammad & ms.Yathrib Mashallah The Microscope An instrument that produces enlarged images of small objects. The purpose for using microscope is to magnify a small object or to magnify the fine details of a larger object in order to examine fine specimen...

ZOOLOGY First LAB. ms. Rasha mohammad & ms.Yathrib Mashallah The Microscope An instrument that produces enlarged images of small objects. The purpose for using microscope is to magnify a small object or to magnify the fine details of a larger object in order to examine fine specimens that cannot be seen by the naked eye. Microscopes types:- 1. Light (optical) microscope: Light microscope involves use of optical lenses and light radiations. The parts of optical compound microscope: A- Ocular lenses (eyepieces): one or two removable lenses that you look through to observe the microscope slide.Typically, these lenses have a magnification of 10X. One of the oculars may have a pointer used to identify a specific area of the study sample on the slide B- Head (or body tube): It connects the eyepiece to the objective lenses  C- Arm: the straight or curved vertical part. It connects the body tube to the base. One hand should be around the arm when carrying the microscope (the other hand should be under the base). D- Base: It supports the weight of the microscope. It contains light source. E- Light source (illuminator): It sends light upward through the condenser lens and through the hole in the stage onto the specimen on the slide. Older microscopes used mirror to reflect light upwards. F- Revolving/Rotating Nose Piece: the objective lenses are attached to it. Rotating the nosepiece allows you to switch between the different lenses. G- Objective lenses: usually a microscope have a three or four objective lenses mounted on a revolving nosepiece (rotating disc). Most microscope have objective lenses with magnifications of 4X (scanning), 10X (low), 40X (high), and 100X (Oil immersion).  H- Coarse adjustment knob: the first knob you should use, and always under low power. Never use it in high power. I- Fine adjustment knob: the second knob you should use under higher power for exact focusing. Both knobs move the stage up and down to help put the specimen in focus. J -Stage: flat platform where you place the slide that contains the specimen. You can able to move the slide by turning two knobs, moves slide left and right. k-Stage clips: the stage clips secure the slide on the stage. L- Condenser: the lens under the stage that focuses light from the illuminator through to the hole in the stage. M- Iris Diaphragm: located beneath the condenser. It contains a dial that rotates to adjust the amount of light that reaches the specimen. 2-Electron microscope The electron microscope uses an electron beam to create an image with electromagnets acting as lenses.There are two types of electron microscope, Transmission Electron Microscope (TEM) and Scanning Electron Microscope (SEM).