Title: Observing Bacteria and Blood
Purpose: The purpose of this experiment is to learn how to use a compound microscope and an oil immersion lens while observing prepared bacterial slides. Additionally, it will be necessary to prepare slides so as to observe bacterial cultures from yogurt as well as to observe the composition of blood (i.e. red blood cells, white blood cells, and platelets).
Exercise 1: Viewing Prepared Slides
To begin this lab experiment I first constructed my incubator using a small Styrofoam cooler and a standard 7 watt light bulb. Next, I read and reviewed the Science Lab Safety Reinforcement Agreement and the instructions on care and use of the compound microscope and oil immersion lens. After setting up my lab station I cleaned the ocular lenses and began to view the six prepared slides with 10x and 40x objectives.
For each slide the difference in the magnification was noticeable and the 40x magnification gave a clearer observation of the specimen. It took a bit of practice to learn the most effective way to adjust the focus and the best placement and adjustment of the stage and clips. However, once I had practiced with the letter “e” slide it was much easier to navigate the remaining slides in the set. One immediate observation of the letter “e” slide was that it was the mirror image when viewed through the microscope.
After completing the observations of the six prepared slides I then introduced the oil immersion lens to the experiment. What I observed immediately using the oil immersion lens was a great amount of magnification and clarity. The specimens were highly focused and it was possible to view individual cells.
Exercise 2: Observing Bacteria Cultures in Yogurt
In preparation for viewing the yogurt slide it was necessary to place a teaspoon of yogurt in a container that could then be placed inside the incubator for 12-24 hours. When I removed the sample from the incubator I used a toothpick to remove a sample which was placed upon a slide. I viewed the slide under 10x, 40x, and 100x magnification. Under lower magnification it was very difficult to distinguish any particular cell types; however, with higher magnification it was possible to observe the various bacterial shapes.
Exercise 3: Preparing and Observing a Blood Slide
In this portion of the lab experiment I used a droplet of blood that I prepared on a slide. Once the slide was set up I viewed the specimen with the 10x, 40x, and 100x oil immersion.
|Amoeba |10x- pink with a dark pink nucleus, |40x- Larger in size, contained more |100x- Large cytoplasmic shape with a large | | |some were grey- dead before |dark spots |pink nucleus | | |staining?, no distinct shapes | | | |Paramecium |10x- Double purple cells, pointed on |40x- larger but same as 10x |100x- Tri-layered membrane, light purple, | | |one end, dark purple nucleus |magnification- edges appeared smooth |darker pink in middle with 2 dark purple | | | | |nucleus- division in center of specimen. Hair| | | | |like structures on the membrane | |Penicillium |10x- green- smooth on one side and |40x- small, many dark jagged cells |100x- Very long threadlike (light green), | | |jagged on the other |separated from the smooth side...
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