Day 2 - Oil Immersion

We learned how to use the oil immersion part of the microscope.  Oil immersion helps us to more clearly see the bacteria we stained.

If the angle of the lens is wider, it can receive more light and thus have a greater resolving power.  The greater the resolving power, the greater the resolution of the image.  Oil immersion helps keep air from bending light away from the slides, so that the microscope receives more light for greater resolution. 

Materials:
Light microscope
Immersion oil
Prepared microscope slide

Procedure:
1.  Position the microscope on the lab table so it will not fall off the edge.  Position its height so that you can comfortably view the slides.
2.  Clean the lenses with lens paper. 
3.  Plug in the microscope, and turn on the light.
4.  Raise the condenser to the highest level.
5.  Prepare the slide if needed.  Place the slide with the specimen facing upwards.  Use the slide holders to keep the slide in place.
6.  If needed, adjust the distance between the ocular lenses so that only one image of the slide is seen.
7.  Look through the 10X objective lens.  Use the coarse and fine focus knobs to bring the image into clear focus.  Adjust the light intensity if needed by moving the diaphragm lever.
8.  Rotate the nosepiece so that you are looking through the 40X objective.  Adjust only the fine focus as necessary for the sharpest image.
9.  Turn the objectives so that the nosepiece is between 40X and 100X.  Place a drop of immersion oil on the place of the slide you want to see.
10.  Rotate the objectives so that you look through the 100X objective.  Be sure that the objective is touching the oil but not the slide. 

11.  After the observations, raise the objectives or lower the stage (depending on the type of microscope) so that there is enough room to remove the slide.  Using lens paper, remove the oil from the 100X objective.
12.  Chart any results that were ascertained from the slide.  Turn of the microscope light, unplug it, cover it, and put it away.