Always Always Always wash your hands and work surface before beginning. Always Always wash your hands thoroughly and work surface before leaving.

Always Always Always Wear laboratory apron when you are working in the lab.

Always Always Always Use goggles when flame or fume is present. Glasses is preferred than contact lenses in the lab.

Always Always Always Use Heat-resistant Gloves for hand protection when handling hot materials, chemicals, organisms that could be harmful. Always Always Keep your hands away from your face and mouth.

Always Always Always keep hair pulled back. Always Always Remove or tie back any article of clothing or jewelry they can hang down or touch chemical or biohazard.

Always Always Always Keep your laboratory area clean and free of unnecessary books, papers, and equipment.

Always Always Always Know the location of the fire extinguisher, fire blanket, eyewash station, and first aid kit.

NEVER Never Never eat, drink or smoke in a laboratory. Never Never have a food or drink in the lab. Never Never apply cosmetics in the lab.

NEVER Avoid Avoid getting corrosive materials or poisons on your skin or clothing, or in your eyes. Do not Inhale the vapors. Do not touch broken glassware. Do not touch broken glassware. Poison

NEVER Never Never “horse around” or play practical jokes in the laboratory. Never Never eat or drink from laboratory glassware.

Be Careful Handle sharp things eg. scalpels,razor,scissors, Handle sharp things eg. scalpels,razor,scissors, pins, blades with extreme care. pins, blades with extreme care.

Be Careful

NEVER Treat all microorganisms as if they were harmful. Treat all microorganisms as if they were harmful. Never Never touch the end of tool that touches bacteria.

NEVER Never Never through biohazard material in the regular trash.

What’s wrong??

Light Microscope Is one of many tools and techniques that allow us to study the cells that are between 1 and 100 µm. 1 micrometer (µm) = mm =10 -6 m 1 nanometer (nm) = µm = m

Electron microscope is used to revealed many organisms and sub cellular structure that were impossible to resolve with the light microscope.

The size range of cell

Compound Light Microscope

Parts of light microscope:-

The functions of microscopic parts:- Ocular lens (Eye Piece)—The part you look at with your eye. Usually 10 X magnification. Head – Reflects light up to the viewers eye. Arm (Neck) – Used to safely transport microscope. Stage – Slides are placed on this. Coarse Adjustment – Used to make large changes in focus. Never use this when viewing on high power. Fine Adjustment – Used to small adjustments of focus. Base – Used to safely transport the microscope. Nose pies (Rotating Objects) – Allows for quick change of objectives. Stage Clips – Use to keep the slide in place. Diaphragm – Use to vary the amount of light passing through the slide. Usually it is better if the amount of light is low. Illumination (Light Source) – Sends light up through the diaphragm and through the slide for viewing

Objective lenses:- The objective lenses are closer to specimen, they are four: Low power (4 x) Medium power (10 x) High power (40 x) Oil immersion (100 x) The ocular lenses magnify specimen by factor (10) so, a total magnification of specific objective lenses: Lower power (40 x) Medium power (100 x) High power (400 x) Oil immersion (1000 x)

Why do we use the oil immersion: The most important lens for microbiology is the oil immersion lens because: it’s the highest magnification It decreases the refraction of light between the glass of lens and the slide It obtains a clear, finely detailed image.

General Guideline 1. Carry the microscope carefully with both hand beneath the base and one hand on the arm. 2. Do not slope the microscope. 3. Observe the slide with eyes open to avoid eye strain. 4. Always focus slowly and carefully. 5. Before using the oil immersion lens have your slide in focus under high power.