General Biology lab Microscope Microscope is an instrument

General Biology lab Microscope

• Microscope – is an instrument used to view small samples or object. • Type of microscope: 1. 2. Light microscope Use visible light which its resolution is limited to around 0. 2 µm Electron microscope Uses electron beam with a far smaller wavelength to gain higher resolution

Parts of Microscope 1. Base : – aboard heavy structure that support the microscope. 2. Light source : – lamp attached directly to the microscope that provide the beam of light necessary for microscope observation. 3. Stage : – the horizontal surface on which the slide is placed. 4. Sub-stage condenser lenses system : – is a system located immediately under the stage , focuses light on the specimen.

5. Arm: – is the curved back that supports the upper parts of the microscope. 6. Body tube: – is the hollow housing through which light travels to the ocular. 7. Ocular lens: – is the part through which a person looks. 8. Objective lens: – The lower lens. 9. Turret or nosepiece: – allowing rapid changing of objective lenses.

10. Coarse and focus adjustment : – found on both side of the arm often contains a pointer to aid in locating objects within the field in view. 11. stage clips : – to hold the slide in place.

Type of objective Lenses 1. Scanning Objective Lens 2. Low Power Objective Lens 3. High Dry Objective Lens 4. Oil Immersion Objective Lens

Scanning Objective Lens Has red band around it. Magnifies objects 4 x. Total magnification = 40 x

Low Power Objective Lens Has yellow band around it. Magnifies objects 10 x. Total magnification = 100 x

High Dry Objective Lens Has blue band around it. Magnifies objects 40 x. Total magnification = 400 x

Oil Immersion Objective Lens Has black and white band around it Magnifies objects 100 x. Total magnification = 1000 x

Magnification • The total magnification can be calculated by multiplying the objective lens value by the ocular lens value. – Ocular magnification = 10 x – Objective magnification • • Scanning Objective Lens = 4 x Low Power Objective Lens = 10 x High Dry Objective Lens = 40 x Oil Immersion Objective Lens = 100 x

Magnification • Total magnification=(ocular lens )x(objective lens) • Example – Total magnification of Scanning Objective Lens = (10 x) X (4 x) = 40 x

General remarks when using the microscope 1. When carry the microscope, upright with one hand around the arm and the other under the base.

2. Before using the microscope you have to be sure that all lenses are clean and keep the stage always dry and clean. 3. Check to be sure the light is on. 4. Position the slide on the stage of the microscope 5. Use the coarse focus knob on the lowest objective only. NEVER use coarse focus on high power or oil immersion, or you may damage the objective lenses. 6. Use both eyes when looking in the microscope