Friday, September 23, 2011

Use A Compound Light Microscope For Lab Procedures

Compound microscopes are used in many fields of study to magnify objects we otherwise would not be able to see. A compound microscope uses two lenses, the ocular lens and the objective lens, to provide magnification. A light source is typically built in to provide illumination, which increases the clarity of the object being magnified. Care must be taken when using compound microscopes: they have many small intricate parts that can break and are expensive to repair. Using proper procedures will ensure that you use the compound microscope effectively and keep it in good condition.


Instructions


1. Carry the microscope to a flat and sturdy surface, using one hand to hold main shaft from the eye piece to the base and the other hand to hold it from the base.


2. Turn on the light source and place the slide or material on the stage. The proper position for the sample is directly over the light source.


3. Set the microscope to the lowest objective powered lens and use the coarse and fine focus knobs to bring the image into focus. Always look into the ocular lens with both eyes open, resisting the urge to close one eye and squint with the other which will increase the strain and tension on your eyes.


4. Adjust the diaphragm as needed to allow more or reduce the amount of light let in.








5. Switch to higher magnification powers as needed, refocusing each time if needed. Some compound microscopes are parfocal, meaning they will remain in focus even if you change magnification.








6. Wipe the lenses with lens paper if dirty then cover the microscope once finished.

Tags: light source, compound microscope, hand hold, ocular lens